automatic css sprite generator

 The sprite factory is a ruby library that can be used to generate
 CSS sprites. It combines individual image files from a directory
 into a single unified sprite image and creates an appropriate CSS
 stylesheet for use in your web application.
 .
 The library provides:
  * both a ruby API and a command line script.
  * many customizable options.
  * support for multiple layout algorithms - horizontal, vertical or
    packed.
  * support for any stylesheet syntax, including CSS and Sass.
  * support for any image library, including RMagick and ChunkyPNG.
  * support for any css selector style, including :hover pseudo-class
    selectors.
  * support for pngcrush'n the generated image file.
  * compatible with Rails 3.1 asset pipeline.