answer:I don’t think it can be done, and if so, why doing that? It will affects the computer’s performance. On Windows 7 I don’t find a way to do that, but you can make a replacement of the background picture every X minutes, so if you have 5 picture that every one of them has a slight change in motion, it may look like your bacground is animated, but it just few picture or slideshow change after a while.