Have you noticed that in many of the old cabinet photos the sitters are obviously only holding the banjo as a prop. Some even hold the banjo upside down. Most players of the instrument instinctively place their fingers on the 'home chords' whereas those who have no concept of the instrument grab it around the neck. I think it was a thing of fashion to be photographed holding the popular instrument of the day.
perfectly right , Ray ; just an accessory available in the photographic ' studio s, exactly like , most of the time , suits , hats , or soldier ' s uniform ; this give absolutly no idea ' bout the fellow on the photo or about the period of the photo