fix inconsistent image filename extensions (#9638)

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@7891 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/attachment.rb

@@ -123,7 +123,7 @@ class Attachment < ActiveRecord::Base
   end
 
   def image?
-    self.filename =~ /\.(jpe?g|gif|png)$/i
+    self.filename =~ /\.(bmp|gif|jpg|jpe|jpeg|png)$/i
   end
 
   def is_text?