diff --git a/app/assets/javascripts/diffs/components/diff_content.vue b/app/assets/javascripts/diffs/components/diff_content.vue
index 42d09e44768..ba6dcd63880 100644
--- a/app/assets/javascripts/diffs/components/diff_content.vue
+++ b/app/assets/javascripts/diffs/components/diff_content.vue
@@ -45,6 +45,9 @@ export default {
     isTextFile() {
       return this.diffFile.viewer.name === 'text';
     },
+    errorMessage() {
+      return this.diffFile.viewer.error;
+    },
     diffFileCommentForm() {
       return this.getCommentFormForDiffFile(this.diffFile.file_hash);
     },
@@ -75,7 +78,7 @@ export default {
 
 <template>
   <div class="diff-content">
-    <div class="diff-viewer">
+    <div v-if="!errorMessage" class="diff-viewer">
       <template v-if="isTextFile">
         <empty-file-viewer v-if="diffFile.empty" />
         <inline-diff-view
@@ -129,5 +132,8 @@ export default {
         </div>
       </diff-viewer>
     </div>
+    <div v-else class="diff-viewer">
+      <div class="nothing-here-block" v-html="errorMessage"></div>
+    </div>
   </div>
 </template>
diff --git a/app/controllers/projects/blob_controller.rb b/app/controllers/projects/blob_controller.rb
index 60fabd15333..ff286c0ccf0 100644
--- a/app/controllers/projects/blob_controller.rb
+++ b/app/controllers/projects/blob_controller.rb
@@ -260,7 +260,7 @@ class Projects::BlobController < Projects::ApplicationController
       extension: blob.extension,
       size: blob.raw_size,
       mime_type: blob.mime_type,
-      binary: blob.raw_binary?,
+      binary: blob.binary?,
       simple_viewer: blob.simple_viewer&.class&.partial_name,
       rich_viewer: blob.rich_viewer&.class&.partial_name,
       show_viewer_switcher: !!blob.show_viewer_switcher?,
diff --git a/app/helpers/blob_helper.rb b/app/helpers/blob_helper.rb
index 4c8e1b209c0..3dea0975beb 100644
--- a/app/helpers/blob_helper.rb
+++ b/app/helpers/blob_helper.rb
@@ -193,7 +193,7 @@ module BlobHelper
 
   def open_raw_blob_button(blob)
     return if blob.empty?
-    return if blob.raw_binary? || blob.stored_externally?
+    return if blob.binary? || blob.stored_externally?
 
     title = 'Open raw'
     link_to icon('file-code-o'), blob_raw_path, class: 'btn btn-sm has-tooltip', target: '_blank', rel: 'noopener noreferrer', title: title, data: { container: 'body' }
diff --git a/app/helpers/diff_helper.rb b/app/helpers/diff_helper.rb
index b6844d36052..32431959851 100644
--- a/app/helpers/diff_helper.rb
+++ b/app/helpers/diff_helper.rb
@@ -138,30 +138,6 @@ module DiffHelper
     !diff_file.deleted_file? && @merge_request && @merge_request.source_project
   end
 
-  def diff_render_error_reason(viewer)
-    case viewer.render_error
-    when :too_large
-      "it is too large"
-    when :server_side_but_stored_externally
-      case viewer.diff_file.external_storage
-      when :lfs
-        'it is stored in LFS'
-      else
-        'it is stored externally'
-      end
-    end
-  end
-
-  def diff_render_error_options(viewer)
-    diff_file = viewer.diff_file
-    options = []
-
-    blob_url = project_blob_path(@project, tree_join(diff_file.content_sha, diff_file.file_path))
-    options << link_to('view the blob', blob_url)
-
-    options
-  end
-
   def diff_file_changed_icon(diff_file)
     if diff_file.deleted_file?
       "file-deletion"
diff --git a/app/helpers/snippets_helper.rb b/app/helpers/snippets_helper.rb
index c7d31f3469d..8fded0efe4d 100644
--- a/app/helpers/snippets_helper.rb
+++ b/app/helpers/snippets_helper.rb
@@ -110,7 +110,7 @@ module SnippetsHelper
 
   def embedded_snippet_raw_button
     blob = @snippet.blob
-    return if blob.empty? || blob.raw_binary? || blob.stored_externally?
+    return if blob.empty? || blob.binary? || blob.stored_externally?
 
     snippet_raw_url = if @snippet.is_a?(PersonalSnippet)
                         raw_snippet_url(@snippet)
diff --git a/app/models/blob.rb b/app/models/blob.rb
index 66a0925c495..c5766eb0327 100644
--- a/app/models/blob.rb
+++ b/app/models/blob.rb
@@ -102,7 +102,7 @@ class Blob < SimpleDelegator
   # If the blob is a text based blob the content is converted to UTF-8 and any
   # invalid byte sequences are replaced.
   def data
-    if binary?
+    if binary_in_repo?
       super
     else
       @data ||= super.encode(Encoding::UTF_8, invalid: :replace, undef: :replace)
@@ -149,7 +149,7 @@ class Blob < SimpleDelegator
   # an LFS pointer, we assume the file stored in LFS is binary, unless a
   # text-based rich blob viewer matched on the file's extension. Otherwise, this
   # depends on the type of the blob itself.
-  def raw_binary?
+  def binary?
     if stored_externally?
       if rich_viewer
         rich_viewer.binary?
@@ -161,7 +161,7 @@ class Blob < SimpleDelegator
         true
       end
     else
-      binary?
+      binary_in_repo?
     end
   end
 
@@ -180,7 +180,7 @@ class Blob < SimpleDelegator
   end
 
   def readable_text?
-    text? && !stored_externally? && !truncated?
+    text_in_repo? && !stored_externally? && !truncated?
   end
 
   def simple_viewer
@@ -220,7 +220,7 @@ class Blob < SimpleDelegator
   def simple_viewer_class
     if empty?
       BlobViewer::Empty
-    elsif raw_binary?
+    elsif binary?
       BlobViewer::Download
     else # text
       BlobViewer::Text
diff --git a/app/models/blob_viewer/base.rb b/app/models/blob_viewer/base.rb
index eaaf9af1330..df6b9bb2f0b 100644
--- a/app/models/blob_viewer/base.rb
+++ b/app/models/blob_viewer/base.rb
@@ -16,7 +16,7 @@ module BlobViewer
 
     def initialize(blob)
       @blob = blob
-      @initially_binary = blob.binary?
+      @initially_binary = blob.binary_in_repo?
     end
 
     def self.partial_path
@@ -52,7 +52,7 @@ module BlobViewer
     end
 
     def self.can_render?(blob, verify_binary: true)
-      return false if verify_binary && binary? != blob.binary?
+      return false if verify_binary && binary? != blob.binary_in_repo?
       return true if extensions&.include?(blob.extension)
       return true if file_types&.include?(blob.file_type)
 
@@ -72,7 +72,7 @@ module BlobViewer
     end
 
     def binary_detected_after_load?
-      !@initially_binary && blob.binary?
+      !@initially_binary && blob.binary_in_repo?
     end
 
     # This method is used on the server side to check whether we can attempt to
diff --git a/app/models/concerns/blob_like.rb b/app/models/concerns/blob_like.rb
index f20f01486a5..dc80f8d62f4 100644
--- a/app/models/concerns/blob_like.rb
+++ b/app/models/concerns/blob_like.rb
@@ -28,7 +28,7 @@ module BlobLike
     nil
   end
 
-  def binary?
+  def binary_in_repo?
     false
   end
 
diff --git a/app/models/diff_viewer/base.rb b/app/models/diff_viewer/base.rb
index 1176861a827..527ee33b83b 100644
--- a/app/models/diff_viewer/base.rb
+++ b/app/models/diff_viewer/base.rb
@@ -18,7 +18,7 @@ module DiffViewer
 
     def initialize(diff_file)
       @diff_file = diff_file
-      @initially_binary = diff_file.binary?
+      @initially_binary = diff_file.binary_in_repo?
     end
 
     def self.partial_path
@@ -48,7 +48,7 @@ module DiffViewer
 
     def self.can_render_blob?(blob, verify_binary: true)
       return true if blob.nil?
-      return false if verify_binary && binary? != blob.binary?
+      return false if verify_binary && binary? != blob.binary_in_repo?
       return true if extensions&.include?(blob.extension)
       return true if file_types&.include?(blob.file_type)
 
@@ -70,20 +70,49 @@ module DiffViewer
     end
 
     def binary_detected_after_load?
-      !@initially_binary && diff_file.binary?
+      !@initially_binary && diff_file.binary_in_repo?
     end
 
     # This method is used on the server side to check whether we can attempt to
-    # render the diff_file at all. Human-readable error messages are found in the
-    # `BlobHelper#diff_render_error_reason` helper.
+    # render the diff_file at all. The human-readable error message can be
+    # retrieved by #render_error_message.
     def render_error
       if too_large?
         :too_large
       end
     end
 
+    def render_error_message
+      return unless render_error
+
+      _("This %{viewer} could not be displayed because %{reason}. You can %{options} instead.") %
+        {
+          viewer: switcher_title,
+          reason: render_error_reason,
+          options: render_error_options.to_sentence(two_words_connector: _(' or '), last_word_connector: _(', or '))
+        }
+    end
+
     def prepare!
       # To be overridden by subclasses
     end
+
+    private
+
+    def render_error_options
+      options = []
+
+      blob_url = Gitlab::Routing.url_helpers.project_blob_path(diff_file.repository.project,
+                                                               File.join(diff_file.content_sha, diff_file.file_path))
+      options << ActionController::Base.helpers.link_to(_('view the blob'), blob_url)
+
+      options
+    end
+
+    def render_error_reason
+      if render_error == :too_large
+        _("it is too large")
+      end
+    end
   end
 end
diff --git a/app/models/diff_viewer/image.rb b/app/models/diff_viewer/image.rb
index c356c2ca50e..350bef1d42a 100644
--- a/app/models/diff_viewer/image.rb
+++ b/app/models/diff_viewer/image.rb
@@ -9,6 +9,6 @@ module DiffViewer
     self.extensions = UploaderHelper::IMAGE_EXT
     self.binary = true
     self.switcher_icon = 'picture-o'
-    self.switcher_title = 'image diff'
+    self.switcher_title = _('image diff')
   end
 end
diff --git a/app/models/diff_viewer/rich.rb b/app/models/diff_viewer/rich.rb
index 2faa1be6567..5caefa2031c 100644
--- a/app/models/diff_viewer/rich.rb
+++ b/app/models/diff_viewer/rich.rb
@@ -7,7 +7,7 @@ module DiffViewer
     included do
       self.type = :rich
       self.switcher_icon = 'file-text-o'
-      self.switcher_title = 'rendered diff'
+      self.switcher_title = _('rendered diff')
     end
   end
 end
diff --git a/app/models/diff_viewer/server_side.rb b/app/models/diff_viewer/server_side.rb
index 977204e6c97..0877c9dddec 100644
--- a/app/models/diff_viewer/server_side.rb
+++ b/app/models/diff_viewer/server_side.rb
@@ -24,5 +24,17 @@ module DiffViewer
 
       super
     end
+
+    private
+
+    def render_error_reason
+      return super unless render_error == :server_side_but_stored_externally
+
+      if diff_file.external_storage == :lfs
+        _('it is stored in LFS')
+      else
+        _('it is stored externally')
+      end
+    end
   end
 end
diff --git a/app/models/diff_viewer/simple.rb b/app/models/diff_viewer/simple.rb
index 8d28ca5239a..929d8ad5a7e 100644
--- a/app/models/diff_viewer/simple.rb
+++ b/app/models/diff_viewer/simple.rb
@@ -7,7 +7,7 @@ module DiffViewer
     included do
       self.type = :simple
       self.switcher_icon = 'code'
-      self.switcher_title = 'source diff'
+      self.switcher_title = _('source diff')
     end
   end
 end
diff --git a/app/serializers/diff_viewer_entity.rb b/app/serializers/diff_viewer_entity.rb
index 27fba03cb3f..587fa2347fd 100644
--- a/app/serializers/diff_viewer_entity.rb
+++ b/app/serializers/diff_viewer_entity.rb
@@ -4,4 +4,7 @@ class DiffViewerEntity < Grape::Entity
   # Partial name refers directly to a Rails feature, let's avoid
   # using this on the frontend.
   expose :partial_name, as: :name
+  expose :error do |diff_viewer|
+    diff_viewer.render_error_message
+  end
 end
diff --git a/app/views/projects/diffs/_render_error.html.haml b/app/views/projects/diffs/_render_error.html.haml
index c3dc47a56a7..7dbd9897e83 100644
--- a/app/views/projects/diffs/_render_error.html.haml
+++ b/app/views/projects/diffs/_render_error.html.haml
@@ -1,6 +1,2 @@
 .nothing-here-block
-  = _("This %{viewer} could not be displayed because %{reason}.") % { viewer: viewer.switcher_title, reason: diff_render_error_reason(viewer) }
-
-  You can
-  = diff_render_error_options(viewer).to_sentence(two_words_connector: ' or ', last_word_connector: ', or ').html_safe
-  instead.
+  = viewer.render_error_message.html_safe
diff --git a/changelogs/unreleased/fj-fix-lfs-image-comments-diffs.yml b/changelogs/unreleased/fj-fix-lfs-image-comments-diffs.yml
new file mode 100644
index 00000000000..dc1fe5d7417
--- /dev/null
+++ b/changelogs/unreleased/fj-fix-lfs-image-comments-diffs.yml
@@ -0,0 +1,5 @@
+---
+title: Fix bug commenting on LFS images
+merge_request: 23812
+author:
+type: fixed
diff --git a/lib/gitlab/blob_helper.rb b/lib/gitlab/blob_helper.rb
index 488c1d85387..d3e15a79a8b 100644
--- a/lib/gitlab/blob_helper.rb
+++ b/lib/gitlab/blob_helper.rb
@@ -12,7 +12,7 @@ module Gitlab
     end
 
     def viewable?
-      !large? && text?
+      !large? && text_in_repo?
     end
 
     MEGABYTE = 1024 * 1024
@@ -21,7 +21,7 @@ module Gitlab
       size.to_i > MEGABYTE
     end
 
-    def binary?
+    def binary_in_repo?
       # Large blobs aren't even loaded into memory
       if data.nil?
         true
@@ -40,8 +40,8 @@ module Gitlab
       end
     end
 
-    def text?
-      !binary?
+    def text_in_repo?
+      !binary_in_repo?
     end
 
     def image?
@@ -113,7 +113,7 @@ module Gitlab
     def content_type
       # rubocop:disable Style/MultilineTernaryOperator
       # rubocop:disable Style/NestedTernaryOperator
-      @content_type ||= binary_mime_type? || binary? ? mime_type :
+      @content_type ||= binary_mime_type? || binary_in_repo? ? mime_type :
                           (encoding ? "text/plain; charset=#{encoding.downcase}" : "text/plain")
       # rubocop:enable Style/NestedTernaryOperator
       # rubocop:enable Style/MultilineTernaryOperator
diff --git a/lib/gitlab/diff/file.rb b/lib/gitlab/diff/file.rb
index bcbded6be9a..e410d5a8333 100644
--- a/lib/gitlab/diff/file.rb
+++ b/lib/gitlab/diff/file.rb
@@ -3,6 +3,8 @@
 module Gitlab
   module Diff
     class File
+      include Gitlab::Utils::StrongMemoize
+
       attr_reader :diff, :repository, :diff_refs, :fallback_diff_refs, :unique_identifier
 
       delegate :new_file?, :deleted_file?, :renamed_file?,
@@ -232,12 +234,12 @@ module Gitlab
         repository.attributes(file_path).fetch('diff') { true }
       end
 
-      def binary?
-        has_binary_notice? || try_blobs(:binary?)
+      def binary_in_repo?
+        has_binary_notice? || try_blobs(:binary_in_repo?)
       end
 
-      def text?
-        !binary?
+      def text_in_repo?
+        !binary_in_repo?
       end
 
       def external_storage_error?
@@ -279,12 +281,16 @@ module Gitlab
         valid_blobs.map(&:empty?).all?
       end
 
-      def raw_binary?
-        try_blobs(:raw_binary?)
+      def binary?
+        strong_memoize(:is_binary) do
+          try_blobs(:binary?)
+        end
       end
 
-      def raw_text?
-        !raw_binary? && !different_type?
+      def text?
+        strong_memoize(:is_text) do
+          !binary? && !different_type?
+        end
       end
 
       def simple_viewer
@@ -367,19 +373,19 @@ module Gitlab
         return DiffViewer::NotDiffable unless diffable?
 
         if content_changed?
-          if raw_text?
+          if text?
             DiffViewer::Text
           else
             DiffViewer::NoPreview
           end
         elsif new_file?
-          if raw_text?
+          if text?
             DiffViewer::Text
           else
             DiffViewer::Added
           end
         elsif deleted_file?
-          if raw_text?
+          if text?
             DiffViewer::Text
           else
             DiffViewer::Deleted
diff --git a/lib/gitlab/git/blob.rb b/lib/gitlab/git/blob.rb
index 2d25389594e..259a2b7911a 100644
--- a/lib/gitlab/git/blob.rb
+++ b/lib/gitlab/git/blob.rb
@@ -100,7 +100,7 @@ module Gitlab
         @loaded_all_data = @loaded_size == size
       end
 
-      def binary?
+      def binary_in_repo?
         @binary.nil? ? super : @binary == true
       end
 
@@ -174,7 +174,7 @@ module Gitlab
       private
 
       def has_lfs_version_key?
-        !empty? && text? && data.start_with?("version https://git-lfs.github.com/spec")
+        !empty? && text_in_repo? && data.start_with?("version https://git-lfs.github.com/spec")
       end
     end
   end
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index b27efe04966..bd0f2b5d122 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -19,6 +19,9 @@ msgstr ""
 msgid " Status"
 msgstr ""
 
+msgid " or "
+msgstr ""
+
 msgid "%d addition"
 msgid_plural "%d additions"
 msgstr[0] ""
@@ -185,6 +188,9 @@ msgstr ""
 msgid "+ %{moreCount} more"
 msgstr ""
 
+msgid ", or "
+msgstr ""
+
 msgid "- Runner is active and can process any new jobs"
 msgstr ""
 
@@ -6698,7 +6704,7 @@ msgstr ""
 msgid "Third party offers"
 msgstr ""
 
-msgid "This %{viewer} could not be displayed because %{reason}."
+msgid "This %{viewer} could not be displayed because %{reason}. You can %{options} instead."
 msgstr ""
 
 msgid "This GitLab instance does not provide any shared Runners yet. Instance administrators can register shared Runners in the admin area."
@@ -7888,6 +7894,9 @@ msgstr ""
 msgid "https://your-bitbucket-server"
 msgstr ""
 
+msgid "image diff"
+msgstr ""
+
 msgid "import flow"
 msgstr ""
 
@@ -7900,6 +7909,15 @@ msgstr ""
 msgid "issue boards"
 msgstr ""
 
+msgid "it is stored externally"
+msgstr ""
+
+msgid "it is stored in LFS"
+msgstr ""
+
+msgid "it is too large"
+msgstr ""
+
 msgid "latest deployment"
 msgstr ""
 
@@ -8140,6 +8158,9 @@ msgstr ""
 msgid "remove due date"
 msgstr ""
 
+msgid "rendered diff"
+msgstr ""
+
 msgid "reply"
 msgid_plural "replies"
 msgstr[0] ""
@@ -8151,6 +8172,9 @@ msgstr ""
 msgid "source"
 msgstr ""
 
+msgid "source diff"
+msgstr ""
+
 msgid "spendCommand|%{slash_command} will update the sum of the time spent."
 msgstr ""
 
@@ -8172,6 +8196,9 @@ msgstr ""
 msgid "view it on GitLab"
 msgstr ""
 
+msgid "view the blob"
+msgstr ""
+
 msgid "with %{additions} additions, %{deletions} deletions."
 msgstr ""
 
diff --git a/spec/features/merge_request/user_creates_image_diff_notes_spec.rb b/spec/features/merge_request/user_creates_image_diff_notes_spec.rb
index d790bdc82ce..d19408ee87f 100644
--- a/spec/features/merge_request/user_creates_image_diff_notes_spec.rb
+++ b/spec/features/merge_request/user_creates_image_diff_notes_spec.rb
@@ -90,9 +90,6 @@ describe 'Merge request > User creates image diff notes', :js do
 
   %w(inline parallel).each do |view|
     context "#{view} view" do
-      let(:merge_request) { create(:merge_request_with_diffs, :with_image_diffs, source_project: project, author: user) }
-      let(:path)          { "files/images/ee_repo_logo.png" }
-
       let(:position) do
         Gitlab::Diff::Position.new(
           old_path: path,
@@ -108,9 +105,11 @@ describe 'Merge request > User creates image diff notes', :js do
 
       let!(:note) { create(:diff_note_on_merge_request, project: project, noteable: merge_request, position: position) }
 
-      describe 'creating a new diff note' do
+      shared_examples 'creates image diff note' do
         before do
           visit diffs_project_merge_request_path(project, merge_request, view: view)
+          wait_for_requests
+
           create_image_diff_note
         end
 
@@ -132,6 +131,32 @@ describe 'Merge request > User creates image diff notes', :js do
           expect(page).to have_content('image diff test comment')
         end
       end
+
+      context 'when images are not stored in LFS' do
+        let(:merge_request) { create(:merge_request_with_diffs, :with_image_diffs, source_project: project, author: user) }
+        let(:path)          { 'files/images/ee_repo_logo.png' }
+
+        it_behaves_like 'creates image diff note'
+      end
+
+      context 'when images are stored in LFS' do
+        let(:merge_request) { create(:merge_request, source_project: project, target_project: project, source_branch: 'png-lfs', target_branch: 'master', author: user) }
+        let(:path)          { 'files/images/logo-black.png' }
+
+        before do
+          allow(Gitlab.config.lfs).to receive(:enabled).and_return(true)
+          project.update_attribute(:lfs_enabled, true)
+        end
+
+        it 'shows lfs badges' do
+          visit diffs_project_merge_request_path(project, merge_request, view: view)
+          wait_for_requests
+
+          expect(page.all('.diff-file span.label-lfs', visible: :all)).not_to be_empty
+        end
+
+        it_behaves_like 'creates image diff note'
+      end
     end
   end
 
diff --git a/spec/features/merge_request/user_sees_diff_spec.rb b/spec/features/merge_request/user_sees_diff_spec.rb
index 0df9e4bbc1a..04b07525919 100644
--- a/spec/features/merge_request/user_sees_diff_spec.rb
+++ b/spec/features/merge_request/user_sees_diff_spec.rb
@@ -87,20 +87,6 @@ describe 'Merge request > User sees diff', :js do
       let(:current_user) { project.owner }
       let(:branch_name) {"test_branch"}
 
-      def create_file(branch_name, file_name, content)
-        Files::CreateService.new(
-          project,
-          current_user,
-          start_branch: branch_name,
-          branch_name: branch_name,
-          commit_message: "Create file",
-          file_path: file_name,
-          file_content: content
-        ).execute
-
-        project.commit(branch_name)
-      end
-
       it 'escapes any HTML special characters in the diff chunk header' do
         file_content =
           <<~CONTENT
@@ -136,5 +122,61 @@ describe 'Merge request > User sees diff', :js do
         expect(page).to have_css(".line[lang='rust'] .k")
       end
     end
+
+    context 'when file is stored in LFS' do
+      let(:merge_request) { create(:merge_request, source_project: project) }
+      let(:current_user) { project.owner }
+
+      context 'when LFS is enabled on the project' do
+        before do
+          allow(Gitlab.config.lfs).to receive(:enabled).and_return(true)
+          project.update_attribute(:lfs_enabled, true)
+
+          create_file('master', file_name, project.repository.blob_at('master', 'files/lfs/lfs_object.iso').data)
+
+          visit diffs_project_merge_request_path(project, merge_request)
+        end
+
+        context 'when file is an image', :js do
+          let(:file_name) { 'files/lfs/image.png' }
+
+          it 'shows an error message' do
+            expect(page).not_to have_content('could not be displayed because it is stored in LFS')
+          end
+        end
+
+        context 'when file is not an image' do
+          let(:file_name) { 'files/lfs/ruby.rb' }
+
+          it 'shows an error message' do
+            expect(page).to have_content('This source diff could not be displayed because it is stored in LFS')
+          end
+        end
+      end
+
+      context 'when LFS is not enabled' do
+        before do
+          visit diffs_project_merge_request_path(project, merge_request)
+        end
+
+        it 'displays the diff' do
+          expect(page).to have_content('size 1575078')
+        end
+      end
+    end
+
+    def create_file(branch_name, file_name, content)
+      Files::CreateService.new(
+        project,
+        current_user,
+        start_branch: branch_name,
+        branch_name: branch_name,
+        commit_message: "Create file",
+        file_path: file_name,
+        file_content: content
+      ).execute
+
+      project.commit(branch_name)
+    end
   end
 end
diff --git a/spec/features/projects/commits/user_browses_commits_spec.rb b/spec/features/projects/commits/user_browses_commits_spec.rb
index 2159adf49fc..574a8aefd63 100644
--- a/spec/features/projects/commits/user_browses_commits_spec.rb
+++ b/spec/features/projects/commits/user_browses_commits_spec.rb
@@ -93,7 +93,7 @@ describe 'User browses commits' do
 
     it 'shows a blank label' do
       allow_any_instance_of(Gitlab::Diff::File).to receive(:blob).and_return(nil)
-      allow_any_instance_of(Gitlab::Diff::File).to receive(:raw_binary?).and_return(true)
+      allow_any_instance_of(Gitlab::Diff::File).to receive(:binary?).and_return(true)
 
       visit(project_commit_path(project, commit))
 
diff --git a/spec/fixtures/api/schemas/entities/diff_viewer.json b/spec/fixtures/api/schemas/entities/diff_viewer.json
index 19780f49a88..81325cd86c6 100644
--- a/spec/fixtures/api/schemas/entities/diff_viewer.json
+++ b/spec/fixtures/api/schemas/entities/diff_viewer.json
@@ -1,8 +1,20 @@
 {
   "type": "object",
-  "required": ["name"],
+  "required": [
+    "name"
+  ],
   "properties": {
-    "name": { "type": ["string"] }
+    "name": {
+      "type": [
+        "string"
+      ]
+    },
+    "error": {
+      "type": [
+        "string",
+        "null"
+      ]
+    }
   },
   "additionalProperties": false
 }
diff --git a/spec/helpers/diff_helper_spec.rb b/spec/helpers/diff_helper_spec.rb
index 53c010fa0db..5396243f44d 100644
--- a/spec/helpers/diff_helper_spec.rb
+++ b/spec/helpers/diff_helper_spec.rb
@@ -256,43 +256,6 @@ describe DiffHelper do
     end
   end
 
-  context 'viewer related' do
-    let(:viewer) { diff_file.simple_viewer }
-
-    before do
-      assign(:project, project)
-    end
-
-    describe '#diff_render_error_reason' do
-      context 'for error :too_large' do
-        before do
-          expect(viewer).to receive(:render_error).and_return(:too_large)
-        end
-
-        it 'returns an error message' do
-          expect(helper.diff_render_error_reason(viewer)).to eq('it is too large')
-        end
-      end
-
-      context 'for error :server_side_but_stored_externally' do
-        before do
-          expect(viewer).to receive(:render_error).and_return(:server_side_but_stored_externally)
-          expect(diff_file).to receive(:external_storage).and_return(:lfs)
-        end
-
-        it 'returns an error message' do
-          expect(helper.diff_render_error_reason(viewer)).to eq('it is stored in LFS')
-        end
-      end
-    end
-
-    describe '#diff_render_error_options' do
-      it 'includes a "view the blob" link' do
-        expect(helper.diff_render_error_options(viewer)).to include(/view the blob/)
-      end
-    end
-  end
-
   context '#diff_file_path_text' do
     it 'returns full path by default' do
       expect(diff_file_path_text(diff_file)).to eq(diff_file.new_path)
diff --git a/spec/lib/gitlab/blob_helper_spec.rb b/spec/lib/gitlab/blob_helper_spec.rb
index 0b56f8687c3..e057385b35f 100644
--- a/spec/lib/gitlab/blob_helper_spec.rb
+++ b/spec/lib/gitlab/blob_helper_spec.rb
@@ -53,11 +53,11 @@ describe Gitlab::BlobHelper do
 
   describe '#text?' do
     it 'returns true' do
-      expect(blob.text?).to be_truthy
+      expect(blob.text_in_repo?).to be_truthy
     end
 
     it 'returns false' do
-      expect(large_blob.text?).to be_falsey
+      expect(large_blob.text_in_repo?).to be_falsey
     end
   end
 
diff --git a/spec/lib/gitlab/diff/file_spec.rb b/spec/lib/gitlab/diff/file_spec.rb
index b15d22c634a..862590268ca 100644
--- a/spec/lib/gitlab/diff/file_spec.rb
+++ b/spec/lib/gitlab/diff/file_spec.rb
@@ -310,7 +310,7 @@ describe Gitlab::Diff::File do
     context 'when the content changed' do
       context 'when the file represented by the diff file is binary' do
         before do
-          allow(diff_file).to receive(:raw_binary?).and_return(true)
+          allow(diff_file).to receive(:binary?).and_return(true)
         end
 
         it 'returns a No Preview viewer' do
@@ -345,7 +345,7 @@ describe Gitlab::Diff::File do
 
       context 'when the file represented by the diff file is binary' do
         before do
-          allow(diff_file).to receive(:raw_binary?).and_return(true)
+          allow(diff_file).to receive(:binary?).and_return(true)
         end
 
         it 'returns an Added viewer' do
@@ -380,7 +380,7 @@ describe Gitlab::Diff::File do
 
       context 'when the file represented by the diff file is binary' do
         before do
-          allow(diff_file).to receive(:raw_binary?).and_return(true)
+          allow(diff_file).to receive(:binary?).and_return(true)
         end
 
         it 'returns a Deleted viewer' do
@@ -436,7 +436,7 @@ describe Gitlab::Diff::File do
         allow(diff_file).to receive(:deleted_file?).and_return(false)
         allow(diff_file).to receive(:renamed_file?).and_return(false)
         allow(diff_file).to receive(:mode_changed?).and_return(false)
-        allow(diff_file).to receive(:raw_text?).and_return(false)
+        allow(diff_file).to receive(:text?).and_return(false)
       end
 
       it 'returns a No Preview viewer' do
diff --git a/spec/lib/gitlab/diff/lines_unfolder_spec.rb b/spec/lib/gitlab/diff/lines_unfolder_spec.rb
index 8e00c8e0e30..f22c2c90334 100644
--- a/spec/lib/gitlab/diff/lines_unfolder_spec.rb
+++ b/spec/lib/gitlab/diff/lines_unfolder_spec.rb
@@ -185,7 +185,7 @@ describe Gitlab::Diff::LinesUnfolder do
 
   let(:project) { create(:project) }
 
-  let(:old_blob) { Gitlab::Git::Blob.new(data: raw_old_blob) }
+  let(:old_blob) { Blob.decorate(Gitlab::Git::Blob.new(data: raw_old_blob, size: 10)) }
 
   let(:diff) do
     Gitlab::Git::Diff.new(diff: raw_diff,
diff --git a/spec/lib/gitlab/git/blob_spec.rb b/spec/lib/gitlab/git/blob_spec.rb
index 80dd3dcc58e..1bcec04d28f 100644
--- a/spec/lib/gitlab/git/blob_spec.rb
+++ b/spec/lib/gitlab/git/blob_spec.rb
@@ -59,7 +59,7 @@ describe Gitlab::Git::Blob, :seed_helper do
       it { expect(blob.data[0..10]).to eq("*.rbc\n*.sas") }
       it { expect(blob.size).to eq(241) }
       it { expect(blob.mode).to eq("100644") }
-      it { expect(blob).not_to be_binary }
+      it { expect(blob).not_to be_binary_in_repo }
     end
 
     context 'file in root with leading slash' do
@@ -92,7 +92,7 @@ describe Gitlab::Git::Blob, :seed_helper do
       end
 
       it 'does not mark the blob as binary' do
-        expect(blob).not_to be_binary
+        expect(blob).not_to be_binary_in_repo
       end
     end
 
@@ -123,7 +123,7 @@ describe Gitlab::Git::Blob, :seed_helper do
           .with(hash_including(binary: true))
           .and_call_original
 
-        expect(blob).to be_binary
+        expect(blob).to be_binary_in_repo
       end
     end
   end
@@ -196,7 +196,7 @@ describe Gitlab::Git::Blob, :seed_helper do
       it { expect(blob.id).to eq('409f37c4f05865e4fb208c771485f211a22c4c2d') }
       it { expect(blob.data).to eq('') }
       it 'does not mark the blob as binary' do
-        expect(blob).not_to be_binary
+        expect(blob).not_to be_binary_in_repo
       end
     end
 
diff --git a/spec/lib/gitlab/gitaly_client/blobs_stitcher_spec.rb b/spec/lib/gitlab/gitaly_client/blobs_stitcher_spec.rb
index 9db710e759e..742b2872c40 100644
--- a/spec/lib/gitlab/gitaly_client/blobs_stitcher_spec.rb
+++ b/spec/lib/gitlab/gitaly_client/blobs_stitcher_spec.rb
@@ -21,7 +21,7 @@ describe Gitlab::GitalyClient::BlobsStitcher do
       expect(blobs[0].size).to eq(1642)
       expect(blobs[0].commit_id).to eq('f00ba7')
       expect(blobs[0].data).to eq("first-line\nsecond-line")
-      expect(blobs[0].binary?).to be false
+      expect(blobs[0].binary_in_repo?).to be false
 
       expect(blobs[1].id).to eq('abcdef2')
       expect(blobs[1].mode).to eq('100644')
@@ -30,7 +30,7 @@ describe Gitlab::GitalyClient::BlobsStitcher do
       expect(blobs[1].size).to eq(2461)
       expect(blobs[1].commit_id).to eq('f00ba8')
       expect(blobs[1].data).to eq("GIF87a\x90\x01".b)
-      expect(blobs[1].binary?).to be true
+      expect(blobs[1].binary_in_repo?).to be true
     end
   end
 end
diff --git a/spec/models/blob_spec.rb b/spec/models/blob_spec.rb
index e8c03b587e2..05cf242e84d 100644
--- a/spec/models/blob_spec.rb
+++ b/spec/models/blob_spec.rb
@@ -122,14 +122,14 @@ describe Blob do
     end
   end
 
-  describe '#raw_binary?' do
+  describe '#binary?' do
     context 'if the blob is stored externally' do
       context 'if the extension has a rich viewer' do
         context 'if the viewer is binary' do
           it 'returns true' do
             blob = fake_blob(path: 'file.pdf', lfs: true)
 
-            expect(blob.raw_binary?).to be_truthy
+            expect(blob.binary?).to be_truthy
           end
         end
 
@@ -137,7 +137,7 @@ describe Blob do
           it 'return false' do
             blob = fake_blob(path: 'file.md', lfs: true)
 
-            expect(blob.raw_binary?).to be_falsey
+            expect(blob.binary?).to be_falsey
           end
         end
       end
@@ -148,7 +148,7 @@ describe Blob do
             it 'returns false' do
               blob = fake_blob(path: 'file.txt', lfs: true)
 
-              expect(blob.raw_binary?).to be_falsey
+              expect(blob.binary?).to be_falsey
             end
           end
 
@@ -156,7 +156,7 @@ describe Blob do
             it 'returns false' do
               blob = fake_blob(path: 'file.ics', lfs: true)
 
-              expect(blob.raw_binary?).to be_falsey
+              expect(blob.binary?).to be_falsey
             end
           end
         end
@@ -166,7 +166,7 @@ describe Blob do
             it 'returns false' do
               blob = fake_blob(path: 'file.rb', lfs: true)
 
-              expect(blob.raw_binary?).to be_falsey
+              expect(blob.binary?).to be_falsey
             end
           end
 
@@ -174,7 +174,7 @@ describe Blob do
             it 'returns true' do
               blob = fake_blob(path: 'file.exe', lfs: true)
 
-              expect(blob.raw_binary?).to be_truthy
+              expect(blob.binary?).to be_truthy
             end
           end
         end
@@ -184,7 +184,7 @@ describe Blob do
             it 'returns false' do
               blob = fake_blob(path: 'file.ini', lfs: true)
 
-              expect(blob.raw_binary?).to be_falsey
+              expect(blob.binary?).to be_falsey
             end
           end
 
@@ -192,7 +192,7 @@ describe Blob do
             it 'returns true' do
               blob = fake_blob(path: 'file.wtf', lfs: true)
 
-              expect(blob.raw_binary?).to be_truthy
+              expect(blob.binary?).to be_truthy
             end
           end
         end
@@ -204,7 +204,7 @@ describe Blob do
         it 'returns true' do
           blob = fake_blob(path: 'file.pdf', binary: true)
 
-          expect(blob.raw_binary?).to be_truthy
+          expect(blob.binary?).to be_truthy
         end
       end
 
@@ -212,7 +212,7 @@ describe Blob do
         it 'return false' do
           blob = fake_blob(path: 'file.md')
 
-          expect(blob.raw_binary?).to be_falsey
+          expect(blob.binary?).to be_falsey
         end
       end
     end
diff --git a/spec/models/diff_viewer/base_spec.rb b/spec/models/diff_viewer/base_spec.rb
index c90b32c5d77..f4efe5a7b3a 100644
--- a/spec/models/diff_viewer/base_spec.rb
+++ b/spec/models/diff_viewer/base_spec.rb
@@ -58,7 +58,7 @@ describe DiffViewer::Base do
 
       context 'when the binaryness does not match' do
         before do
-          allow_any_instance_of(Blob).to receive(:binary?).and_return(true)
+          allow_any_instance_of(Blob).to receive(:binary_in_repo?).and_return(true)
         end
 
         it 'returns false' do
@@ -141,4 +141,25 @@ describe DiffViewer::Base do
       end
     end
   end
+
+  describe '#render_error_message' do
+    it 'returns nothing when no render_error' do
+      expect(viewer.render_error).to be_nil
+      expect(viewer.render_error_message).to be_nil
+    end
+
+    context 'when render_error error' do
+      before do
+        allow(viewer).to receive(:render_error).and_return(:too_large)
+      end
+
+      it 'returns an error message' do
+        expect(viewer.render_error_message).to include('it is too large')
+      end
+
+      it 'includes a "view the blob" link' do
+        expect(viewer.render_error_message).to include('view the blob')
+      end
+    end
+  end
 end
diff --git a/spec/models/diff_viewer/server_side_spec.rb b/spec/models/diff_viewer/server_side_spec.rb
index 98a8f6d4cc9..86b14b6ebf3 100644
--- a/spec/models/diff_viewer/server_side_spec.rb
+++ b/spec/models/diff_viewer/server_side_spec.rb
@@ -32,4 +32,24 @@ describe DiffViewer::ServerSide do
       end
     end
   end
+
+  describe '#render_error_reason' do
+    context 'when the diff file is stored externally' do
+      before do
+        allow(diff_file).to receive(:stored_externally?).and_return(true)
+      end
+
+      it 'returns error message if stored in LFS' do
+        allow(diff_file).to receive(:external_storage).and_return(:lfs)
+
+        expect(subject.render_error_message).to include('it is stored in LFS')
+      end
+
+      it 'returns error message if stored externally' do
+        allow(diff_file).to receive(:external_storage).and_return(:foo)
+
+        expect(subject.render_error_message).to include('it is stored externally')
+      end
+    end
+  end
 end
diff --git a/spec/support/helpers/fake_blob_helpers.rb b/spec/support/helpers/fake_blob_helpers.rb
index bc9686ed9cf..801ca8b7412 100644
--- a/spec/support/helpers/fake_blob_helpers.rb
+++ b/spec/support/helpers/fake_blob_helpers.rb
@@ -23,7 +23,7 @@ module FakeBlobHelpers
       0
     end
 
-    def binary?
+    def binary_in_repo?
       @binary
     end
 
diff --git a/spec/support/helpers/test_env.rb b/spec/support/helpers/test_env.rb
index d52c40ff4f1..d352a7cdf1a 100644
--- a/spec/support/helpers/test_env.rb
+++ b/spec/support/helpers/test_env.rb
@@ -62,7 +62,8 @@ module TestEnv
     'between-create-delete-modify-move'  => '3f5f443',
     'after-create-delete-modify-move'    => 'ba3faa7',
     'with-codeowners'                    => '219560e',
-    'submodule_inside_folder'            => 'b491b92'
+    'submodule_inside_folder'            => 'b491b92',
+    'png-lfs'                            => 'fe42f41'
   }.freeze
 
   # gitlab-test-fork is a fork of gitlab-fork, but we don't necessarily