His head looks very flattened in relation to the rest of his body in that shorts photo. Was he really that disproportionate?
No. I think you are seeing an artifact of some darkroom work. The image was probably dodged to get an even exposure. Most professional images of Hitler were retouched to produce the best possible presentation. Hitler disliked candid photos and casual snapshots of himself and had them supressed if anyone published them. All the "smiling Hitler with children and dogs" shots that you see in period publications were carefully staged and choreographed.
Yeah, that one with the shorts has obviously been retouched, since the head is out of proportion to the body and the lighting is wrong. The light should be behind him, as you can see by the glare off his leg, but his face is fully lit as if by studio photography lights. I’d guess it was a Soviet propaganda job that was meant to embarass him.