Unsuccessful attempt to properly eager load screenshots.

Currently the virtual attribute "image_url" in the screenshots model
apparently runs one SQL query each to get the packages data.

app/models/screenshot.rb

@@ -4,7 +4,9 @@ class Screenshot < ActiveRecord::Base
   # Return the URL to this screenshot.
   # size: 'small' (thumbnail) or 'large' (full-size)
   # (If possible serve the screenshots statically from the web server.)
+  #attr_accessor :image_url
   def image_url(size)
+    # TODO: Prevents proper eager loading somehow...
     "/screenshots/#{self.package.name[0]}/#{self.package.name}/#{self.id}_#{size}.png"
   end
 end