Paperclip
Easy file attachment management for ActiveRecord
... as installing ImageMagick (which, for most modern Unix-based systems, is as easy as installing the right packages). Attached files are saved to the filesystem and referenced in the browser by an easily understandable specification, which has sensible and useful defaults. Paperclip will wrap up to four attributes (all prefixed with that attachment's name, so you can have multiple attachments per model if you wish) and give them a friendly front end.