diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index d00636d4c..1eef95100 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -774,7 +774,7 @@ module ApplicationHelper
     attachments += obj.attachments if obj.respond_to?(:attachments)
     if attachments.present?
       text.gsub!(/src="([^\/"]+\.(bmp|gif|jpg|jpe|jpeg|png))"(\s+alt="([^"]*)")?/i) do |m|
-        filename, ext, alt, alttext = $1.downcase, $2, $3, $4
+        filename, ext, alt, alttext = $1, $2, $3, $4
         # search for the picture in attachments
         if found = Attachment.latest_attach(attachments, CGI.unescape(filename))
           image_url = download_named_attachment_url(found, found.filename, :only_path => only_path)
diff --git a/test/helpers/application_helper_test.rb b/test/helpers/application_helper_test.rb
index a524c91b8..74acae4b0 100644
--- a/test/helpers/application_helper_test.rb
+++ b/test/helpers/application_helper_test.rb
@@ -156,20 +156,30 @@ RAW
   end
 
   def test_attached_images_with_textile_and_non_ascii_filename
-    attachment = Attachment.generate!(:filename => 'café.jpg')
+    to_test = {
+      'CAFÉ.JPG' => 'CAF%C3%89.JPG',
+      'crème.jpg' => 'cr%C3%A8me.jpg',
+    }
     with_settings :text_formatting => 'textile' do
-      assert_include %(<img src="/attachments/download/#{attachment.id}/caf%C3%A9.jpg" alt="" />),
-        textilizable("!café.jpg!)", :attachments => [attachment])
+      to_test.each do |filename, result|
+        attachment = Attachment.generate!(:filename => filename)
+        assert_include %(<img src="/attachments/download/#{attachment.id}/#{result}" alt="" />), textilizable("!#{filename}!", :attachments => [attachment])
+      end
     end
   end
 
   def test_attached_images_with_markdown_and_non_ascii_filename
     skip unless Object.const_defined?(:Redcarpet)
 
-    attachment = Attachment.generate!(:filename => 'café.jpg')
+    to_test = {
+      'CAFÉ.JPG' => 'CAF%C3%89.JPG',
+      'crème.jpg' => 'cr%C3%A8me.jpg',
+    }
     with_settings :text_formatting => 'markdown' do
-      assert_include %(<img src="/attachments/download/#{attachment.id}/caf%C3%A9.jpg" alt="" />),
-        textilizable("![](café.jpg)", :attachments => [attachment])
+      to_test.each do |filename, result|
+        attachment = Attachment.generate!(:filename => filename)
+        assert_include %(<img src="/attachments/download/#{attachment.id}/#{result}" alt="" />), textilizable("![](#{filename})", :attachments => [attachment])
+      end
     end
   end