S.H.
What about a "1st" party? Have a cake with the number "1", party bags filled with goodies such as a "1" cookie and a small puzzle (I've seen Care Bears, Spiderman, Strawberry Shortcake and many others at the Dollar Tree for ...yes, $1!) :) Add a little tag to the ribbon that says something like, "Thanks for '1' Special Birthday with (fill in child's name)!"
Party City has the "1" pinata and balloons and bibs and so forth; so, it should be easy to find "1" things, if you choose to do it.
I love the photographer idea and so many shared here, by the way!