diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 2a06ad926..d384ffa8b 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -160,8 +160,8 @@ module ApplicationHelper
   end
 
   def thumbnail_tag(attachment)
-    link_to image_tag(url_for(:controller => 'attachments', :action => 'thumbnail', :id => attachment)),
-      {:controller => 'attachments', :action => 'show', :id => attachment, :filename => attachment.filename},
+    link_to image_tag(thumbnail_path(attachment)),
+      named_attachment_path(attachment, attachment.filename),
       :title => attachment.filename
   end
 
diff --git a/config/routes.rb b/config/routes.rb
index 7a1eb663a..061bdf7ba 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -260,7 +260,7 @@ RedmineApp::Application.routes.draw do
   get 'attachments/:id/:filename', :to => 'attachments#show', :id => /\d+/, :filename => /.*/, :as => 'named_attachment'
   get 'attachments/download/:id/:filename', :to => 'attachments#download', :id => /\d+/, :filename => /.*/, :as => 'download_named_attachment'
   get 'attachments/download/:id', :to => 'attachments#download', :id => /\d+/
-  get 'attachments/thumbnail/:id(/:size)', :to => 'attachments#thumbnail', :id => /\d+/, :size => /\d+/
+  get 'attachments/thumbnail/:id(/:size)', :to => 'attachments#thumbnail', :id => /\d+/, :size => /\d+/, :as => 'thumbnail'
   resources :attachments, :only => [:show, :destroy]
 
   resources :groups do
diff --git a/test/unit/helpers/application_helper_test.rb b/test/unit/helpers/application_helper_test.rb
index 506c30cc7..e097efe52 100644
--- a/test/unit/helpers/application_helper_test.rb
+++ b/test/unit/helpers/application_helper_test.rb
@@ -1077,6 +1077,12 @@ RAW
       link_to_attachment(a, :only_path => false)
   end
 
+  def test_thumbnail_tag
+    a = Attachment.find(3)
+    assert_equal '<a href="/attachments/3/logo.gif" title="logo.gif"><img alt="3" src="/attachments/thumbnail/3" /></a>',
+      thumbnail_tag(a)
+  end
+
   def test_link_to_project
     project = Project.find(1)
     assert_equal %(<a href="/projects/ecookbook">eCookbook</a>),