This example on the left shows how much of the photo will be lost by wrapping the canvas around the sides of the frame. Wrapping like this is called "gallery print"

(In our example, there isn't enough room for this style of printing so part of the boy's head has been cut off)

The example on the right shows the same photo printed to a canvas with a solid colour edge (none of the boy's head is lost)

Use this option when your photo has been tightly cropped.