Stretched canvas refers to paintings that are mounted on 1.5-inch thick wooden stretcher bars attached to the back. Wires are included for easy hanging, so you can display the painting on your wall as soon as you receive it. Unstretched canvas, on the other hand, does not have any stretcher bars for support. The artwork will be rolled and shipped in a mailing tube. Once you receive your unstretched painting, you can take it to a local framing shop for stretching or framing. This option includes an additional 3 to 4 inches of canvas on all sides for stretching purposes.