This is the image Amy Joyce found of Bookhout in the Homicide office behind Fritz. Notice the overhead light.
So, that settles it that in this other picture, they are leaving that room with that same lighting fixture.
So, they were in there. They had their interrogation. And now they are coming out. I suspect that was right after the first interrogation because Oswald still has his shirt. They are probably heading to the first lineup at 4:00, and it's known that Bookhout attended that. Bookhout followed Boyd and Sims and Hall who took Oswald to that interrogation. In other words, this is where Bookhout was at that time; so, he should be there in the picture. And he is there; it's just that his face and his dark Fedora hat are covered up by that bogus white hat.