Sounds like a glitch ~ I save many times when I make photo books after a few pages I save so I don't have to re-do the whole thing if something happens.
I had some "glitchy" issues with their site yesterday. I started hitting the save button at the top of the page after every two pages that I did. I'm sorry. That really sucks.
Re: Artscow.com photo book users...help
Sounds like a glitch ~ I save many times when I make photo books after a few pages I save so I don't have to re-do the whole thing if something happens.