I've probably got a copy, but from memory, I think it's just a photograph of Robert Thornburgh holding the banjo but there is no information, except that the banjo is the 'Meal Ticket'.
Here’s a scan of the original photograph that was used for the article, which I think may have been taken by (or at least printed by) Lew Green, who interviewed Van Eps in 1960 (available elsewhere on the site, I believe.) It’s a bit clearer than the halftoned image from the BMG. Again, all this comes via the largesse of Patrick Doyle, who, hailing from your shores, Richard, seems to prove that your fellow countrymen -- Ian et al -- make for some of the most generous folks around.