No,thats not it. I'm not up on all the feature names. It may have been an App or a widget or some other name.
Your wallpaper photos would cycle through the desktop and each time the same photo was shown it would be very different. As if each "filter" in GNU was added to the same photo one at a time as it came around again in the wallpaper folder.
It's hard to describe but I sure do miss it.