ICO libraries for Ruby

• MiniMagick runs the ImageMagick command line from Ruby. ImageMagick reads every ICO entry and writes multi-size icons, so MiniMagick is the simplest way to make favicon.ico or convert icons in Ruby.

Pure-Ruby image gems (ChunkyPNG) don’t read ICO.

• MiniMagick Read and write Windows ICO icons in Ruby with MiniMagick (ImageMagick): list icon sizes, convert ICO to PNG, generate a multi-size favicon.ico, with code.