Windows 7 lets you set up a slideshow of multiple images as the desktop wallpaper by default without you grappling with other Desktop Enhancement tools. Some Windows themes include a slide show, or you can create your own slide show from your personal collection of pictures. Rightclick an empty part of the desktop, select Personalize > Desktop Background, then hold down Ctrl as you click on the images you like. Choose how often you'd like the images to be changed from the drop down box (anything from daily to once every 10 seconds). You can also select Shuffle if you'd like the backgrounds to appear in a random order. Click on Save Changes and you shall be able to enjoy the show on your desktop.