They used to have a web site where you could submit photos but I don't know if they're doing that any more. They also take some photos in the park during the day to use at that night's show.
Rumor right now is that the show is closing 9/3 to be reworked into a similar projection show to premiere again during the holidays. Not sure if it will even include submitted photos in the new show.
It's currently called the Magic, Memories and You show, but I believe will be changing names with the premiere of the new show.