The first photo is definitely morphed. I've seen photos from the same video, and while impressive, his arms didn't look anywhere near that big.
I don't think anyone except Sergio and maybe Larry Scott had 20" arms in the 60's and 70's. A true 20" arm is a freakishly HUGE arm. To put things in perspective, Gunter's arms were recently taped at 22", and he weighs over 300 lb in contest shape. Someone on Getbig measured Lee Priest's arms at a little over 20", and many people say he has the freakiest arms ever.
I'd like to know what you guys are doing to pump your arms up. My arms don't gain much over a quarter inch when pumping up.