Not just any old violent images either. This is the man who wrote a novel with a young school shooter as the protagonist, years before it caught on as a national craze:
“Rage (originally titled Getting It On) is the first novel by Stephen King published under the pseudonym Richard Bachman in 1977.
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Charlie Decker, a Maine high school senior, is called to a meeting with his principal over a previous incident in which Decker attacked his chemistry teacher with a heavy wrench. For unknown reasons, Charlie subjects the principal to a series of insulting remarks, resulting in his expulsion. Charlie storms out of the office and retrieves a pistol from his locker, setting its contents on fire. He then returns to his classroom and fatally shoots his Algebra teacher. The fire triggers an alarm, but Charlie forces his classmates to stay in the classroom, killing another teacher when he enters. As the students and teachers evacuate the school, police and media arrive at the scene.
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The novel’s plot vaguely resembles actual events that have transpired since the book’s publication, to a degree that the author is no longer comfortable with the book being in print for fear that it may inspire similar occurrences (”[Rage is] now out of print.”[1]) as it had already been associated with incidents of high school shootings and hostage takings”
http://en.wikipedia.org/wiki/Rage_%28Stephen_King_novel%29
Several actual school shooters were discovered to have had copies of the book or were known to have been fans of it. So, maybe King has a guilty conscience, since the shootings haven’t stopped even though he stopped printing his book that may have inspired the phenomenon.