More commonly referred to as a desktop background in Windows, a wallpaper is an image that is used as a backdrop on any graphical user interface that has a desktop. More plainly, it is the picture or pattern you see on the main screen after your computer has booted up. In the picture, you can see an example of a Microsoft Windows XP desktop featuring a wallpaper depicting white clouds in a blue sky over a green hill.
Confusion between screen saver and wallpaper
Many new computer users confuse a wallpaper with a screen saver, which is the moving picture or animation shown when you are away from your computer. See our screen saver page for further information and related links on this term.