If the photograph is the symbol of the place, event, person, it may rightfully be called iconic I think. But you may also have a photograph that is just a photograph of something iconic. The man standing in front of the tanks is an iconic moment. It is what comes to mind first for most people when they think of the Tienanmen square massacre. But there are, as the author points, several photographs of the moment. Is there an iconic photograph? Or are there just photographs of the moment that symbolizes the whole event?
I don't buy the author's idea that an image has to be universally iconic to be an icon, as societies use different symbols for common things. Words being an obvious example, because languages differ around the planet, but a tree is still a tree even if it isn't called by that name. Something can be iconic to one group, but be irrelevant to another.
