i have a picture thats like 600 x 400, and im trying to make it into a wallpaper, not like stretch the image out, my canvas is 1280x800 and i want to keep my picture at 600 x 400, im just trying to blend the picture in with a black background or white background or something, right now its just a white canvas with a picture in the middle, how do i make it into a wallpaper and blend it to the background?