easy_imaging

https://github.com/growthcode/easy_imaging

If you are using the Paperclip Gem to store your files but would also like to be able to run manipulate the images in your app, then this is the easiest Gem to get you started. You can use any of the ImageMagick (or even Graphicsmagick) methods. Find a list of image manipulation options here: http://www.imagemagick.org/script/command-line-options.php.