Whose picture did Plato (Sal Mineo) keep in his school locker in the movie "Rebel Without a Cause"?

Alan Ladd

In his article "Dangerous Talents," published in Vanity Fair Magazine in March 2005, Sam Kashner writes that director Nicholas Ray, screenwriter Stewart Stern, costar James Dean, and Sal Mineo himself all intended for Mineo's character Plato to be subtly but definitely understood as gay. Kashner says that although the Production Code was still very much in force and forbade any mention of homosexuality, Ray, Dean, Mineo, and Stern all worked together to insert restrained references to Plato's homosexuality and attraction to Jim, including the pinup photo of Alan Ladd on Plato's locker door, Plato's adoring looks at Jim, his loaded talk with Jim in the old mansion, and even the name "Plato," which is a reference to the Classical Greek philosopher.

http://www.imdb.com/title/tt0048545/trivia