thoughtbot/paperclip — pull request #1137 by invisiblellama (2013-01-13 14:56:40+00:00)
Title: Add support for attachment metadata (currently only image width and height)

If model has _meta attribute, Paperclip will store metadata for all configured styles (image dimensions for now), which can be referenced as attachment.width/attachment.height or attachment.width(:style)/attachment.height(:style)