If my memory serve me right, this is an audition photo. The story behind why Stuart is looking away from the camera is to hide the fact that he can't play the bass guitar correctly. They fear that the judges might spot it so they asked Stuart to look away from the camera.
Nope, that ain't Pete. He's just a sit-in session drummer. This is an early photo of the Beatles during the time they were auditioning and even Stu can't play the bass guitar well t this point that's why he's hiding from the camera so that the judges won't spot his mistakes.