You'll need some kind of a photo/imaging managing program. I have several (they all came with scanners), but one of them, PhotoDeluxe I think, allows you to build albums, and then lets you assign the album as your screen saver. I'm using about 15 different "slide show" shots of SP (including a close up of the "awful Blue Drink, thank you) on my PC's.
There is an option on the AC Home page Photo section that allows you to select an image of AC and then assign it as your screen saver. If you are not so proud that you must have your own photos, that is a quick way to get a pretty good shot.