Someone recently asked about photos of Twain available on-line.
If you have a Compuserve account, you can access a very large
photographic archive, which includes at least two .gif format
photos of Twain for downloading.  (I downloaded one of them, and
it shows Twain at 65-70 yrs.)

I'm sure there are many others on the internet itself.  Have
you accessed any of the Twain-related World Wide Web home pages?

Scott Dalrymple
University at Buffalo