Command-line graphics editors: GraphicsMagick and ImageMagick

GraphicsMagick and ImageMagick are both powerful command-line programs for manipulating various image types. They have similar syntax, except that GraphicsMagick commands start with gm while in ImageMagick different commands have different binaries, so you just type the command name directly. For instance, the command for converting file types to each other in GraphicsMagick is

gm convert originalFile targetFile

while in ImageMagick it would be

convert originalFile targetFile

I have found GraphicsMagick to be the faster of the two packages.