 CONT: When Humbert comes through the door in the beginning of the  movie, he walks by a painting in the hall. Some moments later he is  shot through the same painting on the stair case. When Quilty is  first shot in the leg, a covered chair is visible at the top of the  stairs, it isnt until Humbert reloads and Quilty makes it to the  top of the stairs that we see the painting that he hides behind  before being shot.