Hi buddy, re: eBay's weird policy concerning personalised image vs. digital book, it's best you have a live chat with eBay Customer Support to get to the bottom of it.  You can start the live chat from here:

http://ocsnext.ebay.com.au/ocs/cusr?query=1705&levelHierarchy=2a3a1

Please share with us what you find out, as I'd be interested to know why this difference exists.