Not mine, but ar0n's method using GD should work with any image format that GD can read (this depends on how you compile it, of course). GD supports WBMP images. However, its author reacted1 to the Unisys patent flap by removing GIF support from GD. So you'd have to convert your GIFs to something else before using GD.
1 some people would say he overreacted, but it's his business what to provide. There are people who would be glad to see patches to GD that would allow GIF manipulation. | [reply] |