According to
this site the photo in question first appeared "in an issue of the Stargate Newsletter, Number 9 February-March 1997 Published by Stargate International (no longer in existence)"
Robert O. Dean is said to be the source of the photo and says that it was given to him by another UFO investigator at a UFO conference in Mexico City in 1994. Greg Bishop recently
related the story as the photo being handed to Dean "by a man representing himself as a Mexican policeman." This version seems at odds with Dean's original published statement as to the source.
Various internet discussions I've read about this photo say it is allegedly of an alien from the
1974 Coyame, Chihuahua, Mexico crash although I've not seen any citations for the origination of the story that links this photo to that crash story. I'd be interested in finding out what the official version of all the details surrounding the photo are supposed to be and cited sources for such.
Presumably Dean still has the original print that was given to him so it sure would be nice to get a proper high resolution scan of the print. I wonder why nobody has bothered to do this yet. Also, I know Dean's credibility in general seems to be rather suspect but I'm not sure how he would have been perceived in 1994 in Mexico as a likely candidate to either hand a genuine photo or to be used to propagate a hoax photo.
It's another anonymous photo for which, as Deckard pointed out in the other alien photo thread, we have nothing to reference against.
Personally, I will say that of all the supposed gray photos out there, this is the only one that has ever given me pause and given me the sense that I might actually be looking at an organic creature. If it is a hoax photo of a model it is a far more convincing job than I've ever seen in any Hollywood film and I hope the artist is not languishing in unpaid obscurity somewhere. If it is a model then to my knowledge no one has yet claimed responsibility for it or conclusively shown it to be a prop from a museum or film.
Most of the copies I've seen are closeup headshots like Lavarat posted above. This copy is the largest I've seen as it includes the chest. It seems apparent that even this is a cropped photo so I'd also be curious to know if Dean's original was a square print or cropped. If it was a square print, why was it cropped and what was omitted?
Dean's credibility aside, I'd challenge anyone to present a photo of a gray from any source (Hollywood film prop, pure CGI, etc.) that looks better than this.