RJ, I can see why you'd like a legitimate source like that for a photo for the same reason that we require information be verified by RSs in the text. However, the problem I'm seeing is that it strikes me as simply not feasible. If a photo appears from a reliable source, that photo is going to be copyrighted by that reliable source. There's no way we could claim fair use in that situation. In my experience, almost all non-fair use images are either user-generated, taken from a Flickr (or something similar), or have had their copyright expire. If we limit images to those from reliable sources, we pretty much limit ourselves to only fair use images and images of historical subjects. I think that is simply unreasonable. User-generated images and images released under a free license have a role to play on Wikipedia. I think it is up to us as editors to determine that role. In the examples I gave above, do you find it inappropriate that the articles use images with unclear provenance and/or that are not reliably sourced? If not, why not? My point here is that the question "Says who?" could be asked of pretty much any user-generated image or image taken from Flickr, and I don't see why this article is being held to a different standard.
And I haven't tried very hard to argue for its inclusion because I don't think it's that great of a picture. I just disagree with the grounds on which it is being excluded, namely that we need some form of legitimization for the image. I agree that we should have some method to determine whether or not this photo (or any) accurately represents the subject. I don't think we need to get the photo from an RS to do that because I think that places far too high a burden. I think it is up to us, the editors, to determine whether an image adequately represents the subject. Do I think relying on someone else to say, "Hey this is me being a hipster" is sufficient? Of course not. I, personally, judge the photo based on my own knowledge of hipster aesthetic, and the ironic mustache and flannel shirt are enough for me. While neither of those elements is mentioned in the article, I don't think it should be too hard to find an RS or two that mentions them in connection with hipsters.