Awesome Update on 4th Robert Johnson Photo - Who Has it Now?

I have an awesome June update on that 4th Robert Johnson photo. The Smithsonian Institution inherited it when they were given Mack McCormick's "Monster" collection of music and writings he gathered over the years. It's been in their possession for awhile, yet they didn't publish it with his book about Johnson, "Biography of a Phantom".
So, where is it? Where is that 4th photo of Robert Johnson?