wallpaper - technical definition

A pattern or picture used to represent the desktop surface (screen background) in a graphical user interface (GUI). Although many wallpaper options come with each operating system, third-party wallpaper files are also available, and any digital image can also be used as wallpaper. Many cellphones allow custom wallpapers for their screen backgrounds.

Why Do You Cover a Desktop with Wallpaper?

Years ago, someone who had too many sleepless nights programming must have thought it a great analogy because a screen desktop is vertical like a wall. With Windows XP, Microsoft decided to end the mystery and just call it "Background." However, background images are stored in the "Wallpaper" folder (c:\WINDOWS\Web\Wallpaper).