Anyone can change the background. Just rename your graphic to background.png and replace the default one in the skin\skin name\media folder. It needs to be a png file and should be the same dimensions as the original.
Another cool thing (IMO) is to use the same graphic for your XP desktop so when you start MP, the graphic remains the same and seems as if the desktop icons are magically replaced by MP's.
Another cool thing (IMO) is to use the same graphic for your XP desktop so when you start MP, the graphic remains the same and seems as if the desktop icons are magically replaced by MP's.