Two of them were found by The Wizard, but this first one was found by a man I simply can't remember. He was on the Education Forum, and someone pointed out the lack of images of Bookhout and asked for one, and this guy provided the link to this one, explaining that Oswald went to speak to Bookhout in the hall, and it was the only time Oswald did that.
Oswald asked him, "What have you got against Broby?" with the last word being in question. It is my hunch that Oswald had cited someone who would vouch for him, someone in the intelligence community, and Bookhout disparaged the guy in a general way. So, Oswald asked what he had against him. I consider that a high probability.
Then, here is the first of two images ID'd as Bookhout by the Wizard. It was taken very soon after the Oswald shooting, and I would say about 2 minutes after the shot went off.
That face is way too round to be Jack Ruby. It is definitely not him. And as The Wizard demonstrated with his gif, there is a seamless overlay with Young Bookhout.
And then finally, there is the image from when Oswald was being wheeled out on the stretcher, with Bookhout pulling up the rear. Notice how guilty and uncomfortable he looks. Doesn't he look nervous and uneasy?
That is James Bookhout, a short man, where he is trying to look inconspicuous, but the guilt is written all over his face. Here is the Wizards's gif for him:
And here is a collage that I did which puts them both together.
The truth is: that match is pretty darn good. But keep in mind that that's true despite photographic alterations that were done to each of them. Above, they blackened his eyes and broke his nose and on the bottom, they gave him a goofy ear. Also note that the cutting off of his lower face by the sleeves in the picture is obscuring his looks a lot and hiding the roundness of his face. The long sideburn is also surely fake.
So, I think we are darn lucky to have 3 images of James Bookhout from the assassination weekend when we are not supposed to have any.