There are enough subtle differences to tell that it isnt a photoshop render of the original photo. Thank you for bringing up Photoshop though... as it is the PERECT tool to use to show that this wasnt traced, scanned, or rendered from a photo using photoshop or anything like it. It appears to be, in fact, a scanned original drawing.
I used the helmet as indicated to scale the two images to the same scale. I then layered the drawing over the photo, reduced its opacity to 30%, and tinted it red to show just how much the drawing differs from the photo. You will notice, that while I can make certain parts of the two line up, I cannot make anywhere near all of it line up at any time. There are different angles, sizes, lengths, and none of them are consistent. While is is DARN CLOSE.... its not perfect... as one would expect from a faked image.
No... its IMPERFECT... just as one would expect a hand drawn picture to be. I am sure he looked at the original photo while drawing it, and he has a much better sense of scale than I do... but I have seen artists... WHILE THEY ARE DRAWING MIND YOU... that can do JUST THIS!
I would be willing to bet, that since the sense of scale gets more and more off the further from center that you go, that he started drawing the CENTER Marine first... then worked outwards. While the center Marine is almost dead on to scale, the rest gets further off the farther away from center you get. Keeping proper scale is DARN HARD when hand copying an actual photo or drawing.
Yeah... photoshop will do a lot. If you dont like the picture... fine. Thats your OPINION. If you think its a fake... thats your OPINION too. But if you are gonna trash the guy just because... and with no proof... then keep it to yourself.
Again... great job Madda...