A EventMachine-aware wrapper for the ImageMagick command line. Uses EM.system to execute if available. Requires Ruby 1.9 since it uses Fibers. The internals have also been rewritten to reduce the number of system() calls. These changes together reduced the time required to run my test from 20sec to 5sec versus the stock MiniMagick library.
Based on mini_magick by http://github.com/probablycorey