Wallpaper Shifter is a little program that starts when you login to Windows and picks a random wallpaper from your list. Depending on the wallpaper width and height, it can automagically scale it for you to fit your desktop without deforming it's proportions. It does not remain running in the background so no system resources are used. Optionally you can also delete / change the current wallpaper on demand if you do not like what you see. A shortcut to “Delete current wallpaper” is provided on the desktop.