After Chester puts a dollar bill in Billy's shirt pocket, the bill changes position twice (the first time it is placed so that the portrait is NOT visible, then the edge of the portrait IS visible, then NOT again), all without ever being touched again.
Gwen tells Danny that she recognised him seeing him through the peephole in the motel door, but the door clearly does not have one.
In the last scene, where Burt speaks with the bishop, the camera shot goes from outside the church to inside the bishop's study. A church bell is ringing, and for the first split second inside the church, the sound of the bell is clearly from the outside.