The photos that hung there for a looooong time were in bad need of an update. They changed the photos only just recently, in December. Most, if not all of them were pulled from the vast library of images that were taken this summer and fall by the group that took reference shots all over property as part of the research and development of "standard shots" for Disney's Photopass.
They avoided using photos of guests, because it would require a signed release from the guest for the use of their image. Using photos of cast members and their families eliminated the need for a release.
You may notice that in the photos, college-aged young men and women are perhaps over-represented compared to many of the other age groups and families that visit the characters in much greater numbers. These are the interns who took the photos of each other during the course of the Photopass development project. Using these photos eliminated any need for paying models for a special photo shoot. I know this because I may or may not be in two of the photos hanging there. I will not describe them, because I've probably already spilled too much.
The photo you describe of your daughter sounds very precious, and is doubtless a very special memory. Can you post a scan of it here?
Perhaps you could also share it with Disney in a letter recounting your magical experience, or submit it to Disney Magazine for their letters section.
Just some thoughts....