This is a historical image from www.freeinfosociety.com. They don't say where they got it.

Their URL for it is http://www.freeinfosociety.com/chimage.php?image=history/docholliday2.jpg

This image of "doc" with the bowler hat actually is a print that hangs in the Tombstone Cochise county courthouse museum. That's the only known print. The Denver public library western collection (which was the source of the print according to the Tombstone Museum) does NOT have it-- the curator of the Cochise county courthouse museum and I have asked them. There is nothing on the print itself to indicate its origin, though its location in Tombstone certainly suggests a Fly photo.