Thanks for looking, David. I put the site together this weekend, so it still needs a good bit of work. I was surprised to find that more than half the animals I have still have no attribution. Some of them are rare, so I hope I'll be able to track down who did them eventually. I should mention that the site will always be free to use and that any pictures submitted to put in the zoo will remain the property of the person sending them.
I hope that people will find the site useful. It's nice to be able to do something like this that is actually fun.