Conversation so far:
what is the famous photo of Y. A. Tittle in question?
A photo of a dazed Y. A. Tittle by Morris Berman of the Pittsburgh Post-Gazette is regarded among the most iconic images in American sports and journalism.
what is special about the famous photo of Y. A. Tittle taken by Morris Berman?
Y. A. Tittle, in his 17th and final season, was photographed helmet-less, bloodied and kneeling immediately after having been knocked to the ground.
who was Y. A. Tittle knocked to the ground by in his 17th and final season?
by John Baker of the Pittsburgh Steelers
why was Y. A. Tittle bloodied and kneeling in his famous photo?
having been knocked to the ground
was the famous photo of Y. A. Tittle published in all the papers?
Post-Gazette editors declined to publish the photo, looking for action shots instead.

Question: so how did it become famous?
Self-contained rewrite: so how did the photo of Y.A. Tittle become famous if Post-Gazette editors declined to publish the photo, looking for action shots instead?