I was looking for the shadow of the rifle.
Looking at the box that obscures the rifle it is possible to get a general idea of which way the shadow falls.
It should be possible to see the shadow of the end of the butt of the rifle being cast away and to the left from the PoV of the camera and I believe it is.
In the pic below note the white reflection of the camera flash on the stock of the rifle.
Note, that towards the butt of the rifle this reflection stops abruptly but there is still a dark patch.
I believe the dark patch is shadow which is why it is not reflecting the camera flash:

On a different point - I noticed that there is a box resting on top of the box that obscures most of the rifle.
This means the rifle was slid along the ground from the left or that the rifle was placed in there and at least one box was then placed over the gap. If it wasn't possible to slide the rifle in from the left we can't seriously assume Oswald took the time to mess about putting boxes over where he hid the rifle:

I also note a small white cloth next to the rifle. Is this what Oswald was supposed to have wiped the rifle down with? I can't find any mention of it anywhere.