Since there’s a second monitor on my workplace, I’m using DisplayFusion. It takes care of changing the current background image in a very comfortable way.
I’ve created a list of Multi-Monitor (Dual, Triple, Quad) Wallpaper Sites in the corresponding forum. It’s not that much fun to check if there are new images available manually. So I’ve created this RSS feed. Simply select the sites you are interested in and copy the generated URL into your RSS reader.
If you want to rummage on the indexed pages yourself, here’s the complete list of all the sites: