Hey guys I've got a question. There are a number of sites out there which allows users to create online books, some of them make it so easy that it's literally just "drag and drop" your photos and text, and then the final file is sent to a digital printer where as few as one copy can be printed and mail off to the client. Here are some examples:

http://www.bookemon.com/create-book

http://www.blurb.com/

My question is, what if I wanted to offer bookmaking functionality like this on one of my sites? Is there a software that I can use on the back-end of my site to drive this kind of functionality, or do you suppose these sites were custom-coded from the ground up?