A wallpaper or background (also known as a desktop wallpaper, desktop background, desktop picture or desktop image on computers) is a digital image (photo, drawing etc.) used as a decorative background of a graphical user interface on the screen of a computer, mobile communications device or other electronic device.
On a computer it is usually for the desktop, while on a mobile phone it is usually the background for the 'home' or 'idle' screen. Though most devices come with a default picture, users can usually change it to custom files of their choosing. A mobile wallpaper is a computer wallpaper sized to fit a mobile device such as a mobile phone, personal digital assistant or digital audio player.
The height is often greater than or equal to the width. Wallpapers can typically be downloaded at no cost from various websites for modern phones (such as those running Android, iOS, or Windows Phone operating systems).