It would be nice to have next / previous / random buttons on the detail pages.

I tried to add a couple pictures, and they haven't shown up on the "newest cats" page (and yes, I'm sure I'm not just looking at a cached version). If that's by design, it would probably be a good idea to display a message to that effect after a picture is added (I just got the blank "add a cat" form after submitting my pictures).