Simply put, wallpapers are attractive pictures, which can be applied to any desktop in order to make it a more active to the human eye. The use of wallpapers is not a new concept in fact, it has been around for a while, people use wallpapers to decorate their homes and make their environment more appealing, the same can be said about computer users, the computer wallpaper can be thought as a nice way to motivate the user's work in such computer.
Computer wallpapers come in different sizes and formats, the size of the wallpaper is directly related to the resolution of the image, in other words, if the wallpaper is big, users with bigger displays will be able to use such wallpaper to decorate their background and not lose valuable details. Resolution is very important when it comes to wallpapers, wallpapers with great resolution will not be pixelated. When the user stretches the image in order to fit the background, some users will have a large screen, which needs to be filled with the team at a higher resolution, for instance a 1028X768 image may not be enough to cover your desktop if you have a widescreen monitor that operates at a much higher resolution, on the other hand, people with smaller screens will be able to enjoy a beautiful background picture on their desktop even if the wallpaper doesn't have a great resolution.