It changes your wallpaper at certain intervals. Desktop Changer has the option of being launched when Windows first boots up. When running, it changes your wallpaper at certain intervals (however many minutes you pick. I prefer 5 minutes myself) to the next wallpaper in the list. You can also choose to have Desktop Changer pick the next desktop wallpaper at random.
The latest version also comes with a handy preview window to show you what wallpaper you have currently selected in the list (so that you can switch directly to that wallpaper if you wish). Check out a screen shot of Desktop Changers preferences window (complete with preview).

Requirements:
* NET Framework

The license of this software is Freeware, you can free download and free use this wallpaper tool software.