diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 27930ac94..552a4cde1 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -357,16 +357,15 @@ module ApplicationHelper
       attachments = attachments.sort_by(&:created_on).reverse
       text = text.gsub(/!((\<|\=|\>)?(\([^\)]+\))?(\[[^\]]+\])?(\{[^\}]+\})?)(\S+\.(bmp|gif|jpg|jpeg|png))!/i) do |m|
         style = $1
-        filename = $6
-        rf = Regexp.new(Regexp.escape(filename),  Regexp::IGNORECASE)
+        filename = $6.downcase
         # search for the picture in attachments
-        if found = attachments.detect { |att| att.filename =~ rf }
+        if found = attachments.detect { |att| att.filename.downcase == filename }
           image_url = url_for :only_path => only_path, :controller => 'attachments', :action => 'download', :id => found
           desc = found.description.to_s.gsub(/^([^\(\)]*).*$/, "\\1")
           alt = desc.blank? ? nil : "(#{desc})"
           "!#{style}#{image_url}#{alt}!"
         else
-          "!#{style}#{filename}!"
+          m
         end
       end
     end
diff --git a/test/unit/helpers/application_helper_test.rb b/test/unit/helpers/application_helper_test.rb
index 26ecf50b1..cafa92ef4 100644
--- a/test/unit/helpers/application_helper_test.rb
+++ b/test/unit/helpers/application_helper_test.rb
@@ -89,7 +89,9 @@ class ApplicationHelperTest < HelperTestCase
   def test_attached_images
     to_test = {
       'Inline image: !logo.gif!' => 'Inline image: <img src="/attachments/download/3" title="This is a logo" alt="This is a logo" />',
-      'Inline image: !logo.GIF!' => 'Inline image: <img src="/attachments/download/3" title="This is a logo" alt="This is a logo" />'
+      'Inline image: !logo.GIF!' => 'Inline image: <img src="/attachments/download/3" title="This is a logo" alt="This is a logo" />',
+      'No match: !ogo.gif!' => 'No match: <img src="ogo.gif" alt="" />',
+      'No match: !ogo.GIF!' => 'No match: <img src="ogo.GIF" alt="" />'
     }
     attachments = Attachment.find(:all)
     to_test.each { |text, result| assert_equal "<p>#{result}</p>", textilizable(text, :attachments => attachments) }