Requirements
This extension works best with GraphicsMagick version 1.4+.
Gmagick should work with earlier versions up to GraphicsMagick 1.2.6 but
some features and formats are not supported for these versions.
Windows version of GraphicsMagick is available from the GraphicsMagick
website. To read about the difference between ImageMagick and GraphicsMagick,
check the » FAQ.