Welcome to the Cheatbook PC Game Wallpapers section! On a computer that is provided with a desktop kind of user interface, wallpaper is the background pattern or picture against which desktop menus, icons, and other elements are displayed and moved around. A wallpaper image can be in a JPEG or a GIF file format. Wallpaper is commonly used in Microsoft Windows, Macintosh Mac OS, Linux, and in other operating systems as well. Each operating system provides several pre-installed wallpapers images for the user to choose from. A user can also choose to download and install third-party wallpapers and use one of these instead..