Stream photos from iTunes to iPad
I don't believe you actually can. Home Sharing does have photo sharing support (as you've discovered with your Apple TV), but I don't believe you can stream photos from a computer to an iPad. Movies, TV Shows, Podcasts and the rest, but I don't remember photos from a computer to an iPad were ever supported.

The only way to do it would be to use a third-party app or use iCloud with Photo Stream, if you can work within its limitations.