Thanks for the responses guys. I guess I should clarify that it's not necessary that the content be pushed through the Apple TV or, if done on the Apple TV, has to be browsable via remote on the Apple TV.

I've played with the Photo Station app a little, but it's very strange. It will back up photos taken on the mobile devices to the NAS, but you really don't have a ton of control over how they're stored. I also don't know if the Photo Station app is capable of AirPlay.

Tom, the person I'm helping really wants to store the content on his NAS and view it from there.