Luke Sharrett is just 21, but he’s already had hundreds of photographs published in The New York Times. A year ago, Sharrett began what was supposed to be a three-month stint as the Times’ White House photojournalism intern. But his bosses were so impressed with the quality of his work — and his character — that the internship was extended. Over and over again. Sharrett quickly became just like another member of the press corps. He left the White House a couple of weeks ago to return to Western Kentucky University, but not before getting a nod from the leader of the free world, President Barack Obama himself, and absorbing the wisdom of some of the best photojournalists in the business.