Eliz found a great use for photo contact sheets:
When you need a TINY picture for a project or for your daughter's first locket, I've found that the perfect solution is the contact sheets many photo developers now provide, especially with digital photos. For example, Costco prints a contact sheet of all the photos in the collection you're having printed. If you need even smaller pictures, have them printed as wallet-sized. The example on the contact sheet will be 1/4th the size.
We have a lovely wooden dollhouse for which I've collected pieces since I discovered I was pregnant with a daughter. We now play with it all the time, and decorating said house is always a fun challenge. I'm thinking these tiny photos, "framed" with broken toothpicks or brown electrical tape, would go well on the living room wall!