You're looking at the backs of two different stretch-mounted canvases. This one on the left is 'Gallery Wrapped'. The canvas, (with the picture printed on the front of it), is stretched around a wooden stretcher frame and it's all ready to hang. But instead of just being folded and stapled to the edge of the wooden stretcher frame, notice how the canvas is wrapped all the way round to the back of the frame and stapled at the back. So you can't see the staples from the side. It looks neater. Also, notice how the colour that's printed on the front of the canvas (ie, your portrait, or whatever the design happens to be) comes right around the edge of the frame, instead of the edge just being bare white canvas.

It looks pretty cool. The reason gallery wrap costs a little bit more is because there is additional work involved in the artwork, this takes a little longer to do, it also uses more canvas (ie, a bigger margin round the edge of your print), and more ink.

For various reasons, you probably don't actually need gallery wrap. From the front, it looks just the same as a Standard Wrapped canvas. And if you intend to mount your stretched canvas inside a larger picture frame, you'd be wasting your money having it gallery wrapped, because when it's inside a frame, nobody will be able to see the coloured edges anyway.

This one on the right is the back view of the 'Standard Wrap' stretching method that costs nothing extra. When you order a standard wrap stretch canvas, this is how it will be delivered to you. Just the same as with gallery wrap, the canvas (with the picture printed on the front of it), is stretched around a wooden stretcher frame and it's all ready to hang. This is standard artist's practice, and the plain white unprinted border of white canvas is simply folded round the edges of the frame and stapled or tacked there, so that the edges are bare white canvas. (you can't of course see the printed colour design in the photo above, because we're looking at the back of it)

You can hang it up just like this, or frame it inside a larger picture frame. Doesn’t matter. Looks cool and fashionable as it is. It doesn't affect the quality at all. It's simply a matter of choice.

Standard wrap is fine for most people's purposes, and from the front, it looks just the same as a Gallery Wrapped canvas anyway. And because it's less time-consuming to produce,
it costs nothing extra.