Hal-- Don't know who owns Nick Karanovich's copy, but the photo also appears
on Page 279 of _"Our Famous Guest": Mark Twain in Vienna_, by Carl Dolmetsch
(University of Georgia Press, 1992). The caption reads:

        Mark Twain in the atelier of Theresa Fedorowna Ries,
        Vienna, 1897. (Photo by Scolik. Picture Archives of the
        Austrian National Library.)

Regards,

Mary Leah Christmas