Wallpaper

Wallpaper (also desktop picture and desktop background) is an image used as a background of a graphical user interface on a computer screen or mobile communications device. On a computer it is usually for the desktop, while for a mobile phone it is usually the background for the 'home' or 'idle' screen. Though most devices comes with a default picture, the user can usually change it to a file of their choosing.

"Wallpaper" is the term used in Microsoft Windows before Windows Vista (where it is called the Desktop "Background"), while Mac OS X calls it a "desktop picture" (previously, the term desktop pattern was used to refer to a small pattern that was repeated to fill the screen).