diff --git a/lib/omniauth/strategies/facebook.rb b/lib/omniauth/strategies/facebook.rb
index de2f291..a188fe4 100644
--- a/lib/omniauth/strategies/facebook.rb
+++ b/lib/omniauth/strategies/facebook.rb
@@ -219,14 +219,14 @@ module OmniAuth
 
       def image_url uid, options
         uri_class = options[:secure_image_url] ? URI::HTTPS : URI::HTTP
-        url = uri_class.build({host: 'graph.facebook.com', path: "/#{uid}/picture"})
+        url = uri_class.build({:host => 'graph.facebook.com', :path => "/#{uid}/picture"})
 
         query = if options[:image_size].is_a?(String)
-          { type: options[:image_size] }
+          { :type => options[:image_size] }
         elsif options[:image_size].is_a?(Hash)
           options[:image_size]
         end
-        url.query = URI.encode_www_form(query) if query
+        url.query = Rack::Utils.build_query(query) if query
 
         url.to_s
       end
diff --git a/test/test.rb b/test/test.rb
index b604ded..424238b 100644
--- a/test/test.rb
+++ b/test/test.rb
@@ -118,7 +118,7 @@ class InfoTest < StrategyTestCase
   end
 
   test 'returns the image with width and height specified in the `image_size` option' do
-    @options = { :image_size => { width: 123, height: 987 } }
+    @options = { :image_size => { :width => 123, :height => 987 } }
     raw_info = { 'name' => 'Fred Smith', 'id' => '321' }
     strategy.stubs(:raw_info).returns(raw_info)
     assert_equal 'http://graph.facebook.com/321/picture?width=123&height=987', strategy.info['image']