diff --git a/daemon/create.go b/daemon/create.go
index 7eb9da8f78..1d0a9a5b6e 100644
--- a/daemon/create.go
+++ b/daemon/create.go
@@ -27,7 +27,7 @@ func (daemon *Daemon) ContainerCreate(name string, config *runconfig.Config, hos
 		if daemon.Graph().IsNotExist(err, config.Image) {
 			_, tag := parsers.ParseRepositoryTag(config.Image)
 			if tag == "" {
-				tag = graph.DEFAULTTAG
+				tag = graph.DefaultTag
 			}
 			return "", warnings, fmt.Errorf("No such image: %s (tag: %s)", config.Image, tag)
 		}
diff --git a/daemon/image_delete.go b/daemon/image_delete.go
index ab6e8e8256..3929b13385 100644
--- a/daemon/image_delete.go
+++ b/daemon/image_delete.go
@@ -36,7 +36,7 @@ func (daemon *Daemon) imgDeleteHelper(name string, list *[]types.ImageDelete, fi
 	// FIXME: please respect DRY and centralize repo+tag parsing in a single central place! -- shykes
 	repoName, tag = parsers.ParseRepositoryTag(name)
 	if tag == "" {
-		tag = graph.DEFAULTTAG
+		tag = graph.DefaultTag
 	}
 
 	if name == "" {
diff --git a/graph/export.go b/graph/export.go
index c356a23225..a57c81a8ff 100644
--- a/graph/export.go
+++ b/graph/export.go
@@ -13,16 +13,19 @@ import (
 	"github.com/docker/docker/registry"
 )
 
-// CmdImageExport exports all images with the given tag. All versions
+// ImageExportConfig holds list of names to be exported to a output stream.
+// All images with the given tag and all versions
 // containing the same tag are exported. The resulting output is an
 // uncompressed tar ball.
-// name is the set of tags to export.
-// out is the writer where the images are written to.
 type ImageExportConfig struct {
-	Names     []string
+	// Names is the set of tags to export.
+	Names []string
+	// OutStream is the writer where the images are written to.
 	Outstream io.Writer
 }
 
+// ImageExport exports list of images to a output stream specified in the config.
+// The exported images are archived into a tar when written to the output stream.
 func (s *TagStore) ImageExport(imageExportConfig *ImageExportConfig) error {
 
 	// get image json
@@ -135,7 +138,7 @@ func (s *TagStore) exportImage(name, tempdir string) error {
 		if err != nil {
 			return err
 		}
-		imageInspectRaw, err := s.LookupRaw(n)
+		imageInspectRaw, err := s.lookupRaw(n)
 		if err != nil {
 			return err
 		}
diff --git a/graph/graph.go b/graph/graph.go
index 6312806b56..4a6079c87f 100644
--- a/graph/graph.go
+++ b/graph/graph.go
@@ -152,6 +152,7 @@ func (graph *Graph) restore() error {
 	return nil
 }
 
+// IsNotExist detects whether an image exists by parsing the incoming error message.
 // FIXME: Implement error subclass instead of looking at the error text
 // Note: This is the way golang implements os.IsNotExists on Plan9
 func (graph *Graph) IsNotExist(err error, id string) bool {
@@ -414,7 +415,7 @@ func (graph *Graph) ByParent() map[string][]*image.Image {
 	return byParent
 }
 
-// If the images and layers are in pulling chain, retain them.
+// Retain keeps the images and layers that are in pulling chain so that they are not deleted.
 // If not, they may be deleted by rmi with dangling condition.
 func (graph *Graph) Retain(sessionID string, layerIDs ...string) {
 	graph.retained.Add(sessionID, layerIDs)
diff --git a/graph/graph_unix.go b/graph/graph_unix.go
index 351a84ccad..a07807d221 100644
--- a/graph/graph_unix.go
+++ b/graph/graph_unix.go
@@ -16,10 +16,9 @@ import (
 	"github.com/docker/docker/pkg/system"
 )
 
-// setupInitLayer populates a directory with mountpoints suitable
+// SetupInitLayer populates a directory with mountpoints suitable
 // for bind-mounting dockerinit into the container. The mountpoint is simply an
 // empty file at /.dockerinit
-//
 // This extra layer is used by all containers as the top-most ro layer. It protects
 // the container from unwanted side-effects on the rw layer.
 func SetupInitLayer(initLayer string) error {
diff --git a/graph/graph_windows.go b/graph/graph_windows.go
index 1422705a75..a19b356f73 100644
--- a/graph/graph_windows.go
+++ b/graph/graph_windows.go
@@ -13,7 +13,7 @@ import (
 	"github.com/docker/docker/pkg/archive"
 )
 
-// setupInitLayer populates a directory with mountpoints suitable
+// SetupInitLayer populates a directory with mountpoints suitable
 // for bind-mounting dockerinit into the container. T
 func SetupInitLayer(initLayer string) error {
 	return nil
@@ -106,33 +106,32 @@ func (graph *Graph) storeImage(img *image.Image, layerData archive.ArchiveReader
 
 		defer f.Close()
 
-		return json.NewEncoder(f).Encode(img)
-	} else {
-		// We keep this functionality here so that we can still work with the
-		// VFS driver during development. This will not be used for actual running
-		// of Windows containers. Without this code, it would not be possible to
-		// docker pull using the VFS driver.
-
-		// Store the layer. If layerData is not nil, unpack it into the new layer
-		if layerData != nil {
-			if err := graph.disassembleAndApplyTarLayer(img, layerData, root); err != nil {
-				return err
-			}
-		}
-
-		if err := graph.saveSize(root, int(img.Size)); err != nil {
-			return err
-		}
-
-		f, err := os.OpenFile(jsonPath(root), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))
-		if err != nil {
-			return err
-		}
-
-		defer f.Close()
-
 		return json.NewEncoder(f).Encode(img)
 	}
+	// We keep this functionality here so that we can still work with the
+	// VFS driver during development. This will not be used for actual running
+	// of Windows containers. Without this code, it would not be possible to
+	// docker pull using the VFS driver.
+
+	// Store the layer. If layerData is not nil, unpack it into the new layer
+	if layerData != nil {
+		if err := graph.disassembleAndApplyTarLayer(img, layerData, root); err != nil {
+			return err
+		}
+	}
+
+	if err := graph.saveSize(root, int(img.Size)); err != nil {
+		return err
+	}
+
+	f, err := os.OpenFile(jsonPath(root), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))
+	if err != nil {
+		return err
+	}
+
+	defer f.Close()
+
+	return json.NewEncoder(f).Encode(img)
 }
 
 // TarLayer returns a tar archive of the image's filesystem layer.
@@ -152,15 +151,14 @@ func (graph *Graph) TarLayer(img *image.Image) (arch archive.Archive, err error)
 		}
 
 		return wd.Export(img.ID, wd.LayerIdsToPaths(ids))
-	} else {
-		// We keep this functionality here so that we can still work with the VFS
-		// driver during development. VFS is not supported (and just will not work)
-		// for Windows containers.
-		rdr, err := graph.assembleTarLayer(img)
-		if err != nil {
-			logrus.Debugf("[graph] TarLayer with traditional differ: %s", img.ID)
-			return graph.driver.Diff(img.ID, img.Parent)
-		}
-		return rdr, nil
 	}
+	// We keep this functionality here so that we can still work with the VFS
+	// driver during development. VFS is not supported (and just will not work)
+	// for Windows containers.
+	rdr, err := graph.assembleTarLayer(img)
+	if err != nil {
+		logrus.Debugf("[graph] TarLayer with traditional differ: %s", img.ID)
+		return graph.driver.Diff(img.ID, img.Parent)
+	}
+	return rdr, nil
 }
diff --git a/graph/history.go b/graph/history.go
index 4bb93fc3f9..390a4873e6 100644
--- a/graph/history.go
+++ b/graph/history.go
@@ -67,6 +67,7 @@ func (graph *Graph) CheckDepth(img *image.Image) error {
 	return nil
 }
 
+// History returns a list of ImageHistory for the specified image name by walking the image lineage.
 func (s *TagStore) History(name string) ([]*types.ImageHistory, error) {
 	foundImage, err := s.LookupImage(name)
 	if err != nil {
@@ -101,6 +102,7 @@ func (s *TagStore) History(name string) ([]*types.ImageHistory, error) {
 	return history, err
 }
 
+// GetParent returns the parent image.
 func (graph *Graph) GetParent(img *image.Image) (*image.Image, error) {
 	if img.Parent == "" {
 		return nil, nil
@@ -108,6 +110,7 @@ func (graph *Graph) GetParent(img *image.Image) (*image.Image, error) {
 	return graph.Get(img.Parent)
 }
 
+// GetParentsSize returns the size of the parent.
 func (graph *Graph) GetParentsSize(img *image.Image, size int64) int64 {
 	parentImage, err := graph.GetParent(img)
 	if err != nil || parentImage == nil {
diff --git a/graph/import.go b/graph/import.go
index 2e08e6c840..33207c9b47 100644
--- a/graph/import.go
+++ b/graph/import.go
@@ -13,13 +13,21 @@ import (
 	"github.com/docker/docker/utils"
 )
 
+// ImageImportConfig holds configuration to import a image.
 type ImageImportConfig struct {
-	Changes         []string
-	InConfig        io.ReadCloser
-	OutStream       io.Writer
+	// Changes are the container changes written to top layer.
+	Changes []string
+	// InConfig is the input stream containers layered data.
+	InConfig io.ReadCloser
+	// OutStream is the output stream where the image is written.
+	OutStream io.Writer
+	// ContainerConfig is the configuration of commit container.
 	ContainerConfig *runconfig.Config
 }
 
+// Import allows to download image from  a archive.
+// If the src is a URL, the content is downloaded from the archive. If the source is '-' then the imageImportConfig.InConfig
+// reader will be used to load the image. Once all the layers required are loaded locally, image is then tagged using the tag specified.
 func (s *TagStore) Import(src string, repo string, tag string, imageImportConfig *ImageImportConfig) error {
 	var (
 		sf      = streamformatter.NewJSONStreamFormatter()
diff --git a/graph/list.go b/graph/list.go
index 89b1a93baa..28c83bc264 100644
--- a/graph/list.go
+++ b/graph/list.go
@@ -18,18 +18,24 @@ var acceptedImageFilterTags = map[string]struct{}{
 	"label":    {},
 }
 
+// ImagesConfig defines the criteria to obtain a list of images.
 type ImagesConfig struct {
+	// Filters is supported list of filters used to get list of images.
 	Filters string
-	Filter  string
-	All     bool
+	// Filter the list of images by name.
+	Filter string
+	// All inditest that all the images will be returned in the list, if set to true.
+	All bool
 }
 
-type ByCreated []*types.Image
+// byCreated is a temporary type used to sort list of images on their field 'Created'.
+type byCreated []*types.Image
 
-func (r ByCreated) Len() int           { return len(r) }
-func (r ByCreated) Swap(i, j int)      { r[i], r[j] = r[j], r[i] }
-func (r ByCreated) Less(i, j int) bool { return r[i].Created < r[j].Created }
+func (r byCreated) Len() int           { return len(r) }
+func (r byCreated) Swap(i, j int)      { r[i], r[j] = r[j], r[i] }
+func (r byCreated) Less(i, j int) bool { return r[i].Created < r[j].Created }
 
+// Images provide list of images based on selection criteria.
 func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 	var (
 		allImages  map[string]*image.Image
@@ -144,7 +150,7 @@ func (s *TagStore) Images(config *ImagesConfig) ([]*types.Image, error) {
 		}
 	}
 
-	sort.Sort(sort.Reverse(ByCreated(images)))
+	sort.Sort(sort.Reverse(byCreated(images)))
 
 	return images, nil
 }
diff --git a/graph/load.go b/graph/load.go
index 9c19012795..4d133c3adf 100644
--- a/graph/load.go
+++ b/graph/load.go
@@ -15,7 +15,7 @@ import (
 	"github.com/docker/docker/pkg/chrootarchive"
 )
 
-// Loads a set of images into the repository. This is the complementary of ImageExport.
+// Load uploads a set of images into the repository. This is the complementary of ImageExport.
 // The input stream is an uncompressed tar ball containing images and metadata.
 func (s *TagStore) Load(inTar io.ReadCloser, outStream io.Writer) error {
 	tmpImageDir, err := ioutil.TempDir("", "docker-import-")
@@ -84,7 +84,7 @@ func (s *TagStore) recursiveLoad(address, tmpImageDir string) error {
 	if _, err := s.LookupImage(address); err != nil {
 		logrus.Debugf("Loading %s", address)
 
-		imageJson, err := ioutil.ReadFile(filepath.Join(tmpImageDir, "repo", address, "json"))
+		imageJSON, err := ioutil.ReadFile(filepath.Join(tmpImageDir, "repo", address, "json"))
 		if err != nil {
 			logrus.Debugf("Error reading json: %v", err)
 			return err
@@ -95,7 +95,7 @@ func (s *TagStore) recursiveLoad(address, tmpImageDir string) error {
 			logrus.Debugf("Error reading embedded tar: %v", err)
 			return err
 		}
-		img, err := image.NewImgJSON(imageJson)
+		img, err := image.NewImgJSON(imageJSON)
 		if err != nil {
 			logrus.Debugf("Error unmarshalling json: %v", err)
 			return err
diff --git a/graph/load_unsupported.go b/graph/load_unsupported.go
index 45bdd98be7..7154931f29 100644
--- a/graph/load_unsupported.go
+++ b/graph/load_unsupported.go
@@ -7,6 +7,8 @@ import (
 	"io"
 )
 
+// Load method is implemented here for non-linux and non-windows platforms and
+// may return an error indicating that image load is not supported on other platforms.
 func (s *TagStore) Load(inTar io.ReadCloser, outStream io.Writer) error {
 	return fmt.Errorf("Load is not supported on this platform")
 }
diff --git a/graph/pull.go b/graph/pull.go
index 5612480a38..0cfc457f2d 100644
--- a/graph/pull.go
+++ b/graph/pull.go
@@ -11,12 +11,17 @@ import (
 	"github.com/docker/docker/utils"
 )
 
+// ImagePullConfig stores pull configuration.
 type ImagePullConfig struct {
+	// MetaHeaders store meta data about the image (DockerHeaders with prefix X-Meta- in the request).
 	MetaHeaders map[string][]string
-	AuthConfig  *cliconfig.AuthConfig
-	OutStream   io.Writer
+	// AuthConfig holds authentication information for authorizing with the registry.
+	AuthConfig *cliconfig.AuthConfig
+	// OutStream is the output writer for showing the status of the pull operation.
+	OutStream io.Writer
 }
 
+// Puller is an interface to define Pull behavior.
 type Puller interface {
 	// Pull tries to pull the image referenced by `tag`
 	// Pull returns an error if any, as well as a boolean that determines whether to retry Pull on the next configured endpoint.
@@ -25,6 +30,7 @@ type Puller interface {
 	Pull(tag string) (fallback bool, err error)
 }
 
+// NewPuller returns a new instance of an implementation conforming to Puller interface.
 func NewPuller(s *TagStore, endpoint registry.APIEndpoint, repoInfo *registry.RepositoryInfo, imagePullConfig *ImagePullConfig, sf *streamformatter.StreamFormatter) (Puller, error) {
 	switch endpoint.Version {
 	case registry.APIVersion2:
@@ -47,6 +53,7 @@ func NewPuller(s *TagStore, endpoint registry.APIEndpoint, repoInfo *registry.Re
 	return nil, fmt.Errorf("unknown version %d for registry %s", endpoint.Version, endpoint.URL)
 }
 
+// Pull downloads a image with specified name and tag from the repo.
 func (s *TagStore) Pull(image string, tag string, imagePullConfig *ImagePullConfig) error {
 	var sf = streamformatter.NewJSONStreamFormatter()
 
@@ -126,7 +133,8 @@ func (s *TagStore) Pull(image string, tag string, imagePullConfig *ImagePullConf
 	return lastErr
 }
 
-func WriteStatus(requestedTag string, out io.Writer, sf *streamformatter.StreamFormatter, layersDownloaded bool) {
+// writeStatus shows status of the pull command.
+func writeStatus(requestedTag string, out io.Writer, sf *streamformatter.StreamFormatter, layersDownloaded bool) {
 	if layersDownloaded {
 		out.Write(sf.FormatStatus("", "Status: Downloaded newer image for %s", requestedTag))
 	} else {
diff --git a/graph/pull_v1.go b/graph/pull_v1.go
index f8df392042..5eb75372ff 100644
--- a/graph/pull_v1.go
+++ b/graph/pull_v1.go
@@ -80,9 +80,9 @@ func (p *v1Puller) pullRepository(askedTag string) error {
 	if askedTag == "" {
 		tagsList, err = p.session.GetRemoteTags(repoData.Endpoints, p.repoInfo.RemoteName)
 	} else {
-		var tagId string
-		tagId, err = p.session.GetRemoteTag(repoData.Endpoints, p.repoInfo.RemoteName, askedTag)
-		tagsList[askedTag] = tagId
+		var tagID string
+		tagID, err = p.session.GetRemoteTag(repoData.Endpoints, p.repoInfo.RemoteName, askedTag)
+		tagsList[askedTag] = tagID
 	}
 	if err != nil {
 		if err == registry.ErrRepoNotFound && askedTag != "" {
@@ -222,7 +222,7 @@ func (p *v1Puller) pullRepository(askedTag string) error {
 	if len(askedTag) > 0 {
 		requestedTag = utils.ImageReference(p.repoInfo.LocalName, askedTag)
 	}
-	WriteStatus(requestedTag, out, p.sf, layersDownloaded)
+	writeStatus(requestedTag, out, p.sf, layersDownloaded)
 	return nil
 }
 
diff --git a/graph/pull_v2.go b/graph/pull_v2.go
index a70529754a..6c2fa20653 100644
--- a/graph/pull_v2.go
+++ b/graph/pull_v2.go
@@ -95,7 +95,7 @@ func (p *v2Puller) pullV2Repository(tag string) (err error) {
 		layersDownloaded = layersDownloaded || pulledNew
 	}
 
-	WriteStatus(taggedName, p.config.OutStream, p.sf, layersDownloaded)
+	writeStatus(taggedName, p.config.OutStream, p.sf, layersDownloaded)
 
 	return nil
 }
diff --git a/graph/push.go b/graph/push.go
index 6e844aada3..9095ae6afe 100644
--- a/graph/push.go
+++ b/graph/push.go
@@ -10,13 +10,19 @@ import (
 	"github.com/docker/docker/registry"
 )
 
+// ImagePushConfig stores push configuration.
 type ImagePushConfig struct {
+	// MetaHeaders store meta data about the image (DockerHeaders with prefix X-Meta- in the request).
 	MetaHeaders map[string][]string
-	AuthConfig  *cliconfig.AuthConfig
-	Tag         string
-	OutStream   io.Writer
+	// AuthConfig holds authentication information for authorizing with the registry.
+	AuthConfig *cliconfig.AuthConfig
+	// Tag is the specific variant of the image to be pushed, this tag used when image is pushed. If no tag is provided, all tags will be pushed.
+	Tag string
+	// OutStream is the output writer for showing the status of the push operation.
+	OutStream io.Writer
 }
 
+// Pusher is an interface to define Push behavior.
 type Pusher interface {
 	// Push tries to push the image configured at the creation of Pusher.
 	// Push returns an error if any, as well as a boolean that determines whether to retry Push on the next configured endpoint.
@@ -25,6 +31,7 @@ type Pusher interface {
 	Push() (fallback bool, err error)
 }
 
+// NewPusher returns a new instance of an implementation conforming to Pusher interface.
 func (s *TagStore) NewPusher(endpoint registry.APIEndpoint, localRepo Repository, repoInfo *registry.RepositoryInfo, imagePushConfig *ImagePushConfig, sf *streamformatter.StreamFormatter) (Pusher, error) {
 	switch endpoint.Version {
 	case registry.APIVersion2:
@@ -51,6 +58,8 @@ func (s *TagStore) NewPusher(endpoint registry.APIEndpoint, localRepo Repository
 }
 
 // FIXME: Allow to interrupt current push when new push of same image is done.
+
+// Push a image to the repo.
 func (s *TagStore) Push(localName string, imagePushConfig *ImagePushConfig) error {
 	var sf = streamformatter.NewJSONStreamFormatter()
 
diff --git a/graph/push_v2.go b/graph/push_v2.go
index b8011bc139..869347df6e 100644
--- a/graph/push_v2.go
+++ b/graph/push_v2.go
@@ -87,12 +87,12 @@ func (p *v2Pusher) pushV2Repository(tag string) error {
 func (p *v2Pusher) pushV2Tag(tag string) error {
 	logrus.Debugf("Pushing repository: %s:%s", p.repo.Name(), tag)
 
-	layerId, exists := p.localRepo[tag]
+	layerID, exists := p.localRepo[tag]
 	if !exists {
 		return fmt.Errorf("tag does not exist: %s", tag)
 	}
 
-	layer, err := p.graph.Get(layerId)
+	layer, err := p.graph.Get(layerID)
 	if err != nil {
 		return err
 	}
diff --git a/graph/registry.go b/graph/registry.go
index 9b744ed681..974235b21a 100644
--- a/graph/registry.go
+++ b/graph/registry.go
@@ -27,7 +27,7 @@ func (dcs dumbCredentialStore) Basic(*url.URL) (string, string) {
 	return dcs.auth.Username, dcs.auth.Password
 }
 
-// v2 only
+// NewV2Repository creates a v2 only repository.
 func NewV2Repository(repoInfo *registry.RepositoryInfo, endpoint registry.APIEndpoint, metaHeaders http.Header, authConfig *cliconfig.AuthConfig) (distribution.Repository, error) {
 	ctx := context.Background()
 
diff --git a/graph/service.go b/graph/service.go
index a7b9b49359..1ab7485e4c 100644
--- a/graph/service.go
+++ b/graph/service.go
@@ -10,7 +10,7 @@ import (
 	"github.com/docker/docker/api/types"
 )
 
-func (s *TagStore) LookupRaw(name string) ([]byte, error) {
+func (s *TagStore) lookupRaw(name string) ([]byte, error) {
 	image, err := s.LookupImage(name)
 	if err != nil || image == nil {
 		return nil, fmt.Errorf("No such image %s", name)
diff --git a/graph/tags.go b/graph/tags.go
index a96ad94bfe..7ea782fe96 100644
--- a/graph/tags.go
+++ b/graph/tags.go
@@ -24,8 +24,10 @@ import (
 	"github.com/docker/libtrust"
 )
 
-const DEFAULTTAG = "latest"
+// DefaultTag defines the default tag used when performing images related actions and no tag string is specified
+const DefaultTag = "latest"
 
+// TagStore contains information to push and pull to the repo.
 type TagStore struct {
 	path         string
 	graph        *Graph
@@ -41,16 +43,17 @@ type TagStore struct {
 	trustService    *trust.TrustStore
 }
 
+// Repository maps image id to image tag.
 type Repository map[string]string
 
-// update Repository mapping with content of u
+// Update updates repository mapping with content of repository 'u'.
 func (r Repository) Update(u Repository) {
 	for k, v := range u {
 		r[k] = v
 	}
 }
 
-// return true if the contents of u Repository, are wholly contained in r Repository
+// Contains returns true if the contents of u Repository, are wholly contained in r Repository.
 func (r Repository) Contains(u Repository) bool {
 	for k, v := range u {
 		// if u's key is not present in r OR u's key is present, but not the same value
@@ -61,6 +64,7 @@ func (r Repository) Contains(u Repository) bool {
 	return true
 }
 
+// TagStoreConfig holds tag store configuration.
 type TagStoreConfig struct {
 	Graph    *Graph
 	Key      libtrust.PrivateKey
@@ -69,6 +73,7 @@ type TagStoreConfig struct {
 	Trust    *trust.TrustStore
 }
 
+// NewTagStore creates a tag store to specified path.
 func NewTagStore(path string, cfg *TagStoreConfig) (*TagStore, error) {
 	abspath, err := filepath.Abs(path)
 	if err != nil {
@@ -121,12 +126,13 @@ func (store *TagStore) reload() error {
 	return nil
 }
 
+// LookupImage returns the image from the store.
 func (store *TagStore) LookupImage(name string) (*image.Image, error) {
 	// FIXME: standardize on returning nil when the image doesn't exist, and err for everything else
 	// (so we can pass all errors here)
 	repoName, ref := parsers.ParseRepositoryTag(name)
 	if ref == "" {
-		ref = DEFAULTTAG
+		ref = DefaultTag
 	}
 	var (
 		err error
@@ -152,7 +158,7 @@ func (store *TagStore) LookupImage(name string) (*image.Image, error) {
 	return img, nil
 }
 
-// Return a reverse-lookup table of all the names which refer to each image
+// ByID returns a reverse-lookup table of all the names which refer to each image.
 // Eg. {"43b5f19b10584": {"base:latest", "base:v1"}}
 func (store *TagStore) ByID() map[string][]string {
 	store.Lock()
@@ -172,6 +178,7 @@ func (store *TagStore) ByID() map[string][]string {
 	return byID
 }
 
+// ImageName returns name of the image.
 func (store *TagStore) ImageName(id string) string {
 	if names, exists := store.ByID()[id]; exists && len(names) > 0 {
 		return names[0]
@@ -179,6 +186,7 @@ func (store *TagStore) ImageName(id string) string {
 	return stringid.TruncateID(id)
 }
 
+// DeleteAll removes images identified by a specific id from the store.
 func (store *TagStore) DeleteAll(id string) error {
 	names, exists := store.ByID()[id]
 	if !exists || len(names) == 0 {
@@ -199,6 +207,7 @@ func (store *TagStore) DeleteAll(id string) error {
 	return nil
 }
 
+// Delete removes a repo identified by a given name from the store
 func (store *TagStore) Delete(repoName, ref string) (bool, error) {
 	store.Lock()
 	defer store.Unlock()
@@ -231,10 +240,13 @@ func (store *TagStore) Delete(repoName, ref string) (bool, error) {
 	return deleted, store.save()
 }
 
+// Tag adds a new tag to an existing image.
 func (store *TagStore) Tag(repoName, tag, imageName string, force bool) error {
 	return store.SetLoad(repoName, tag, imageName, force, nil)
 }
 
+// SetLoad stores the image to the store.
+// If the imageName is already in the repo then a '-f' flag should be used to replace existing image.
 func (store *TagStore) SetLoad(repoName, tag, imageName string, force bool, out io.Writer) error {
 	img, err := store.LookupImage(imageName)
 	store.Lock()
@@ -319,6 +331,7 @@ func (store *TagStore) SetDigest(repoName, digest, imageName string) error {
 	return store.save()
 }
 
+// Get returns a repo from the store.
 func (store *TagStore) Get(repoName string) (Repository, error) {
 	store.Lock()
 	defer store.Unlock()
@@ -332,6 +345,7 @@ func (store *TagStore) Get(repoName string) (Repository, error) {
 	return nil, nil
 }
 
+// GetImage returns an image from a given repo from the store.
 func (store *TagStore) GetImage(repoName, refOrID string) (*image.Image, error) {
 	repo, err := store.Get(repoName)
 
@@ -361,6 +375,7 @@ func (store *TagStore) GetImage(repoName, refOrID string) (*image.Image, error)
 	return nil, nil
 }
 
+// GetRepoRefs returns list of repos.
 func (store *TagStore) GetRepoRefs() map[string][]string {
 	store.Lock()
 	reporefs := make(map[string][]string)
@@ -375,7 +390,7 @@ func (store *TagStore) GetRepoRefs() map[string][]string {
 	return reporefs
 }
 
-// Validate the name of a repository
+// validateRepoName validates the name of a repository.
 func validateRepoName(name string) error {
 	if name == "" {
 		return fmt.Errorf("Repository name can't be empty")
diff --git a/graph/tags_unit_test.go b/graph/tags_unit_test.go
index 8dffb2a6bc..5effb5c6fc 100644
--- a/graph/tags_unit_test.go
+++ b/graph/tags_unit_test.go
@@ -119,17 +119,17 @@ func TestLookupImage(t *testing.T) {
 		testOfficialImageName + ":" + testOfficialImageID,
 		testOfficialImageName + ":" + testOfficialImageIDShort,
 		testOfficialImageName,
-		testOfficialImageName + ":" + DEFAULTTAG,
+		testOfficialImageName + ":" + DefaultTag,
 		"docker.io/" + testOfficialImageName,
-		"docker.io/" + testOfficialImageName + ":" + DEFAULTTAG,
+		"docker.io/" + testOfficialImageName + ":" + DefaultTag,
 		"index.docker.io/" + testOfficialImageName,
-		"index.docker.io/" + testOfficialImageName + ":" + DEFAULTTAG,
+		"index.docker.io/" + testOfficialImageName + ":" + DefaultTag,
 		"library/" + testOfficialImageName,
-		"library/" + testOfficialImageName + ":" + DEFAULTTAG,
+		"library/" + testOfficialImageName + ":" + DefaultTag,
 		"docker.io/library/" + testOfficialImageName,
-		"docker.io/library/" + testOfficialImageName + ":" + DEFAULTTAG,
+		"docker.io/library/" + testOfficialImageName + ":" + DefaultTag,
 		"index.docker.io/library/" + testOfficialImageName,
-		"index.docker.io/library/" + testOfficialImageName + ":" + DEFAULTTAG,
+		"index.docker.io/library/" + testOfficialImageName + ":" + DefaultTag,
 	}
 
 	privateLookups := []string{
@@ -138,7 +138,7 @@ func TestLookupImage(t *testing.T) {
 		testPrivateImageName + ":" + testPrivateImageID,
 		testPrivateImageName + ":" + testPrivateImageIDShort,
 		testPrivateImageName,
-		testPrivateImageName + ":" + DEFAULTTAG,
+		testPrivateImageName + ":" + DefaultTag,
 	}
 
 	invalidLookups := []string{
diff --git a/hack/make/validate-lint b/hack/make/validate-lint
index 5995af21d0..c3cb716599 100644
--- a/hack/make/validate-lint
+++ b/hack/make/validate-lint
@@ -25,6 +25,7 @@ packages=(
 	daemon/network
 	docker
 	dockerinit
+	graph
 	image
 	integration-cli
 	pkg/chrootarchive