Problem
Your carefully planned photo suffers if it loses important "breathing space" to the wrapped edges of a canvas. And you don't want black, white or plain colour edges that can look ugly.Solution
Use an enlarged, blurred version of the image to sit underneath/behind your photo or design. I used Photoshop but all art apps should allow you to do similar.This is the original image I'm using. You'll notice that the "breathing space" around the poem is already a little cramped. No way it can afford to lose any more to the wrap.
So that's the starting image, uploaded to Zazzle and placed on a wrapped canvas. Next, the blured version.
Here it is after applying a gaussian blur in Photoshop with a very large radius - 250px on this image, which is 10,000px wide
Again, uploaded to Zazzle and then placed underneath the original. Here's the in-progress wrapped canvas in Zazzle's design tool
You can see the original image is selected, with the blurred version underneath and enlarged enough to more than cover the edges as well. How much you enlarge will depend on the characteristics of your photo to give a pleasing blend.
Here's detail of the edge. If you carefully resize your photo to just touch the dotted, green guide lines, you'll get the edges flush as shown
I think you'll agree that it looks much better than plain edges and the colours of course blend with the photo.
Enjoy :)
PS See the finished product on Zazzle