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'
Though most devices comes with a default picture, users can usually
change it to files 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).