Gas Giant Generator:

This is a cgi script that I wrote to generate pictures of random gas giants. It is not in any way, shape, or form based on real physics, chemistry, astronomy, or even astrology. It's just art. To create the program, I first played around in the GIMP until I could reliably generate good looking planets by a combination of filters. Then I re-implemented versions of each filter that I used. The hardest part was the first step: creating a good-looking gradient. The major issue was that computers have no taste whatsoever, and giving them taste is hard. This program still doesn't have much taste, but it's better. Todo: add more hue variation, add secondary and tertiary colors (Jupiter is red with yellow), remove ugly browns. Allow generation of maps rather than globes. Allow different sizes (or just a larger size). For more details on the process, read the source.
Enter the seed for the random number generator. Enter 0 to use the current time.