Update: The iPhone version of this software is now available! Please visit www.percolatorapp.com/ The current iPhone version limits the resolution of the input image, due to the computational complexity, but I was able to design the app so the output still has it's own unique qualities.
The software that produced these images employs an original algorithm I designed in 2005 that can fit circles into an image, based on "best-fit", "largest-first", simple color harmony and placement heuristics (when there's multiple spots to place a single circle).
See the set description for more details.
The source images in this set are in the public domain. They are part of the Great Images In NASA series: grin.hq.nasa.gov/