Images have a rhetorical or persuasive quality that is often times far more explicit and immediate than words. The government can say Bin Laden is dead, but until we can see things with our own eyes we are less inclined to believe.
However, even before the release of the so-called Bin Laden death picture, Americans have been primed for such an occurrence for more than a decade. Magazines such as Time have rhetorically silenced the demons by placing an "X" across the faces of Hitler, Saddam Hussein, and of course, Bin Laden. The "X" disambiguates the subject -- the "X" removes all ambiguity from confounding interpretations regarding the status of the individual depicted. Often a rifle's cross-hairs will also be used for the same effect. The "X" neutralizes, targets, and makes known any given threat.
Words can do the same thing. "X" marks the spot, "dead center," or simply "dead" seem to accompany the mental images associated with Bin Laden, as they did for Saddam Hussein and Hilter before him. Media images and the words that contextualize meaning are often metaphors for emotional responses we have yet to comes to terms with. We incorporate, through the media, images that mirror universal likes and dislikes, happiness or anger. Media images represent a cultural and sociological pathology -- one which often masks the pain and dispair we all share when witnessessing, experiencing and trying to make sense of horrific events. This is why "X" is so effectiveness in communicating disambiguity -- the final word, or in this case, the final letter.