To share/copy photos from one Chatbook to another Chatbook:
Log into your account at chatbooks.com and be sure you're under your bookshelf
Click on the book from which you would like to copy photos.
Click "Rearrange pages" at the top right
Select the photos you want to copy over by clicking on them individually.
Click "Copy To" at the bottom of the page
Follow the on-screen instructions.
Your photos will now be in your Chatbook of choice.
If you would like to share photos from one Chatbook to another on the Chatbooks app, click here.