Interesting exhibit. There is something to consider before everyone complains that their favorite photo was left off the list. These are photos which galvanized ACTION from people. The effect of any of these photos cannot be appreciated without an understanding of the social , political, cultural environment of the time in which it was shot. The "people taking action because of the picture" effect is probably more an influence of these three influences than the photo itself. So, these cannot be considered the best photos ever taken.
Though "tank-man" did not stir the world into action,it was complelling and it certainly is a piece of high art, compositionally perfect, and capturing in essence the eternal struggle of the individual against the tyranny of the majority.
To me, that is what defines great art as opposed to momentary calls to action. Masterpieces distill the essence of the human experience, transcending even the circumstances in which the photo was taken.
In this regard, a few in your exhibit I would regard as
masterpieces...certainly the depression era shot,and the Ansel Adams. My favorites off the list? Tank-man, and the picture of Earthrise from the back of the moon.
Thanks for the spread on photography...good work!