I don't think its authenticity should be doubted. According to Charles Lear, Timothy Green Beckley (who recently passed away) snapped the photo while being driven by Jim Moseley. But in Nick Redfern’s 2011 book, The Real Men in Black, Moseley is quoted explaining his thoughts on what they had seen: "The only thing that kind of made sense to me was that he was a look-out for a bookie joint, or some illegal operation. But the point is, to me anyway—not to Tim, I know—it had absolutely nothing to do with the Robertsons or with flying saucers. He might have seen Tim taking his picture out of the car, and if he was doing something illegal that’s why he left." So, the photo itself appears to be perfectly legit; it just has been misinterpreted by others.