I don't think that first photo is from when he was 17 or 18. That looks more like 20 or 21.
19 maybe it, he is massive but lacks later lat thickness and width, he already had humongous arms at 19.
Never seen photo for me!
Just google picture searched.
There is a reddit thread
Says "Arnold 2 months shy of 19"
Well there is nothing to be shy of