Although I remain unconvinced that a portrait can be any picture which contains a human figure, I have enjoyed the posts in this thread, and thank the respondents.
Admittedly, my opinion is worth no more than the paper it is printed on, and since there isn't even any paper, well......that's what it is worth.
Given that, I would humbly submit that the essential nature of a photographic portrait is no different than the art practiced by portrait artists on canvas, with oils, in the past, being a concerted effort to capture the complete essence of the subject in one image. No easy task, and one which leaves much room for editorializing, and hagiography on the one hand and "warts and all" on the other. But, that's a portrait, something which attempts to explain who, exactly, is this person, in one image. Great photos, which happen to have people in the frame, but which leave those people as we found them, a complete mystery to us, are those portraits?
Others may object, a fact to which I have no objection. Let the party continue as it has.
Even though the human element in the photo below is a tiny part of the photo, I know for a fact that it captures the essence of this person in a way that words never will. So, perhaps, portrait.
