Gifsicle

Gifsicle twaddles GIF image files in a variety of ways. It is better than many of the freely available GIF twaddlers on the market -- for one thing, it has more options. It supports merging several GIFs into a GIF animation; exploding an animation into its component frames; changing individual frames in an animation; turning interlacing on and off; adding transparency; adding delays, disposals, and looping to animations; adding or removing comments; flipping and rotation; optimizing animations for space; and changing images' colormaps, among other things. Extensive command-line options control which, if any, of these occur.

Links

 * Archived Site
 * Official Project Site