Installing ImageMagick GraphicsMagick - aheckmann/gm GitHub Wiki

Mac OS X

The easiest way is to install the libraries using brew.

To install graphicsmagick, you need ghostscript. You can install both by running brew install gs graphicsmagick.

To install imagemagick with webp support, you must run brew install imagemagick --with-webp. graphicsmagick does not support webp.