ImageMagick is an image display and manipulation tool for the X
Window System. ImageMagick can read and write JPEG, TIFF, PNM, GIF,
and Photo CD image formats. It can resize, rotate, sharpen, color
reduce, or add special effects to an image, and when finished you can
either save the completed work in the original format or a different
one. ImageMagick also includes command line programs for creating
animated or transparent .gifs, creating composite images, creating
thumbnail images, and more.