It would be neat to provide an "iterations" parameter that runs the algorithm N times over the source image. It could be implemented a slider so the results can be animated, after a fashion.

I did this manually with the seagull photo, and some pretty interesting results occur. The seagull becomes increasingly compressed towards the left, and looks more like a seagull on even iterations than on odd iterations.

Just goes to show how entertaining a simple algorithm can be, nice work!