My recommendation would be for you to compile your photos on the PC to a .mp4 or .mpg movie that can then be imported onto the AppleTV just like any other movie in iTunes.
The rule of thumb should be, if it plays in iTunes, it will play on AppleTV. Use Quicktime Pro, or whatever video editing tool you may be using to create your movie, make sure its in the right format and AppleTV should be able to play it!
Happy New Year! Itay.