A picture says a thousand words

Why does the New York Times use this particular picture of Barack Obama alongside a smiling Clinton (who looks twenty years younger and far more presentable than she does in real life) and McCain? The NYT people must know how powerful a visual representation is. Obama isn't smiling. He isn't showing any teeth. Half his face is in shadow giving the impression of a very dark-skinned black man. And what is that expression, exactly? There are plenty of alternative images that could have been used, such as the one below the NYT triptych. Why did they choose this one?