Sorry for the large pics, but thought it would be easier to see. I made an image in PSE that I uploaded to Shutterfly to see how it would actually print. The way I saved it was as a 12x12 full size flattened jpg. This first picture I have black was the background for 12x12, the pink was set 11.95 inches(I know it says 7.95 inches ...that is for me to see since I print 8x8 books), dark blue is 7.75 inches (11.75 in.) and light blue is 7.50 inches (11.50 in.). In this zoomed photo, I can see the whole image. I set the page for 7.75 inches in shutterfly.
The second photo shows if you choose their full size page layout. You will noticed that the page will get cut off. They have their boundaries set for 7.95 inches for 8x8.
Hoped this helped some of you with visually seeing what would get cut off on your layout at what size. Also, they do have templates for photoshop/pse users to download their template to help as well.
https://www.shutterfly.com/digitalsc...sign-specs.jsp