A lot of "iconic" photos are going to have been ones that appeared in Sports Illustrated and Life. While I agree that the Brandi Chastain shot qualifies in my book, would it be so if it were not on the cover of SI?
To me, the term "iconic photo" can mean both capturing a defining or great moment in sports or one that Runscott said, can picture in your head. It doesn't have to be a once in a lifetime action shot either…that shot of YA Tittle on his knees captures football (and losing) in one simple shot. The shot of Ali over Liston is simply one of the greatest photographs ever, let alone sports. My favorite photo of Babe Ruth is the Nickolas Muray portrait that just shows him in pinstripes with a bat over his shoulder.
With the advent of video and the ability to grab frames, I fear that in time people will not appreciate the skill and mastery of those great sports photographers who captured these images, nor the sometimes blind luck to be in the right place, at the right time.
For us collectors, I believe this photo qualifies as "iconic" maybe for all the wrong reasons