Of course, if you've been drawing Thanos for ten years then you probably don't need a reference because you know all of the proportion and details. But if it is your first time drawing Thanos you do need a reference.
I didn't do that. I used the one picture I posted to figure out the proportions and details.
Furthermore, no one uses the term "copy" in art. You either talk about portrait or subject drawing where the artist tries to illustrate what's in front of him, and then you have tracing—either complete or partial—which is looked down upon because it doesn't take any skill and you don't learn anything from it.
But tracings are very easy to identify because they don't have any variance.
This panel from Iron Man Feat Itself #7.3 and you can immediately identify it as a tracing of this photo that you can find by Googling scared girl.
Actually there I disagree. You don't need to draw a specific character for years to get his proportions right because artists have differen't styles which often are seen in the different approach to the proportions of characters, compare Michael Turner (God bless his soul) to Jim Lee. Most artists who draw people will get the proportions right even of monstrous characters, the way it suits them and their style. You will see Thanos drawn differently, sometimes to the extreme, by different artists. The only thing where the artist might need help are the details of the costume.
As for the tracing part. I don't really care about this as long as the final result looks good. If a photo was traced I don't care, if another artist was traced it's more difficult.
What's wrong with him? He might trace some photos, or copy the poses, reuse some art but the final results look really realistic with near perfect proportions and his talent is obvious because he just copies, traces or whatever, the body but the suit and everything else is still work.
"The Grand Admiral was smart and subtle, but never used his brilliance to show up or humiliate anyone.
He demanded results, but never perfection, and had amazing stores of patience for those who were truly working to their fullest ability.
It was a pity Thrawn's style of leadership hadn't spread through the rest of the navy.
If that happened, he suspected, the Empire would stand forever."