I don't really know why you got downvoted so much for this, other than because people are possibly mistaking your more objective idea of "influential" with a subjective "this is a great/i love this work of art". I can't say its the most influential picture of all time, but I would definitely argue it was the most successful artistically designed propaganda poster for a U.S. presidential campaign, and by successful I mean that it did its job: people believed it, on top of the fact that it was made in the digital age... I mean, this image went viral. I remember seeing this picture as people's facebook profiles who weren't even born in or had ever lived in the united states. The entire world was sick of George Bush and people ate this image up. I would argue that the design team for Obama's campaign was absolutely crucial to him becoming elected.