This script makes a ring system that you can add to a picture of a planet, and was adapted from a Photoshop script. This script is updated for GIMP v2.6
The ring system can be any size from 300x300 to 3000x3000, and can be tilted to any angle. The whirl-and-pinch portion of the script is time consuming, but using at least 8 iterations make the rings look very nice. The thickness of the rings can be controlled using the inner and outer ring ratio values in the script. The closer these two values are together, the narrower the ring.