When you crop your image to fit on a photo canvas, you can move the viewable portion of your image.

After placing your image onto the canvas, you can click and drag the photo up/down or right/left to adjust how it will print on the final product.The parts of the image that are outside of the dotted yellow line will be wrapped around the frame of the canvas, so you will not see those parts of the image on face of the canvas when it is printed.