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.
While customizing a desktop is not a highly important task, some people will feel unproductive use in non-customized machines, because the system is simply not optimized for them. Computer users who are able to optimize their desktop and change the visual effects, in order to fit their personality will be able to perform tasks much better because they feel comfortable with the environment they have created, even if such environment is virtual in nature.