wilderness - 12:58 pm on Dec 7, 2012 (gmt 0)
FWIW, I've thousands of active images.
Until 2000 or 2001, I used "names" for images, until thousands of requests appeared without any viewing of pages (for a popular "0name").
At that time, I began numbering images, and have used that method since.
If you don't know the "fish's" number than your not able to locate the fish. Neither are the SE's (unless you offer alt and/or name text for your images).
Unless your a photographer selling images, there's not any benefit to allowing SE's or other websites to have access to your images. Despite the benefits of added traffic from the images.