It's a given that a better name for a picture is "cat_eating_mouse.jpg" than "Aou7aIw=2.jpg". On my website I'm going to have thousands of pictures. It's not a big of a problem to name them manually, but to come up with a unique name. Say, I have 2 pictures with the same content, the both can be name "cat_eating_mouse.jpg"
How can I make them unique so that's it's still good for SEO? Should I just add a number in the end -- "cat_eating_mouse2.jpg", "cat_eating_mouse3.jpg" ... "cat_eating_mouse155.jpg"?