I'm uncut, so I know how uncut dicks operate - and a guy can easily keep his foreskin over the head when erect, it really just depends on the length and tightness of the foreskin. This guy looks like he has a tight foreskin - a loose one would show some head even when flaccid - and thus it's completely reasonable that his foreskin would completely cover the head when hard.
Furthermore, this guy is OBVIOUSLY hard/semi-hard - there is absolutely no one who has a 100% flaccid dick that looks like that. Anybody who claims to have one is lying. The thickness, length, and vascularization on this cock are clear indicators of a penis in an aroused state. After I ejaculate, my cock usually flops down keeping it's entire length for a couple minutes - I'd guess this guy is in that state.
Fully hard, the size of this guy's dick might expand by a tiny bit, but it wouldn't be much. I'd guess an accurate measurement from base to tip would not be too far over 8 inches. Now most people with a cock like that would claim 10+ inches - and a lot of people would believe it - but I've yet to see legitimate proof of a cock that size. The majority of guys running around claiming to have a 10 inch + cock are probably between 7 to 8 inches when measured accurately. Similarly, half the guys claiming to have 8 inchers are probably more like 6-7. That said, a legitimate 8 inches is really a very large dick - bigger than a lot of people will admit because everyone is hung up on exaggerating their size by an inch or two.