For a simple wallpaper refresh, you can simply point Wally at a folder on your computer and set the interval at which you want the wallpaper to refresh. If you don't have a huge stash of wallpaper, or you're tired of your collection, you can have Wally pull pictures from remote directories via FTP or from any of ten available sources like Bing, SmugMug, Picasa, Buzznet, Photobucket, Pike, Panoramio, Yahoo!, or Flickr.
You can adjust various settings like auto-rotation based on EXIF data, photo selection only if photos are bigger than the desktop and/or landscape as well as how frequently the wallpaper will change and how pictures will be positioned.
Wally is freeware and available for Windows, Mac, and Linux operating systems. Have a favorite wallpaper tool or source for great wallpapers? Let's hear about it in the comments.