attachment_fu and Rmagick FAT thumbnails

I'm using attachment_fu on the project I'm currently working on, using it to process the images the users upload.

As backend I use Rmagick, since it was already used in the same app. At some point I felt curious about the size in kb of the thumbnails generated, to estimate the increase of bandwidth the new feature would add on the server.

I quickly spotted the size of the generated jpegs was unreasonable for the pixel size of them.

It turned out that attachment_fu + Rmagick on Ubuntu 6.0.6 and Ruby 1.4 aren't compressing jpegs.

To fix here's a one line patch on attachment_fu.

this patch sets the jpeg quality to 85%

[~]$ cat atch_fu/attachment_fu_rmagick_compression.patch 
Index: lib/technoweenie/attachment_fu/processors/rmagick_processor.rb
===================================================================
--- lib/technoweenie/attachment_fu/processors/rmagick_processor.rb      (revision 2864)
+++ lib/technoweenie/attachment_fu/processors/rmagick_processor.rb      (working copy)
@@ -45,9 +45,9 @@
           else
             img.change_geometry(size.to_s) { |cols, rows, image| image.resize!(cols, rows) }
           end
-          self.temp_path = write_to_temp_file(img.to_blob)
+          self.temp_path = write_to_temp_file(img.to_blob {self.quality = 85})
         end
       end
     end
   end
-end
\ No newline at end of file
+end