Underswap Sans Wallpapers. 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. Its submitted by processing in the best field. UnderSwap Sans Wallpaper by cjc728 on DeviantArt from cjc728.