Its not like you can just walk up to a wild animal and ask them to sit still for a little while you try to get a closeup of them. Our cheetah interaction experience at Inkwenkwezi Game Reserve outside East London did give me the opportunity to get such a shot of one of their cheetahs. A cheetah's spots are unique like finger prints and no two cheetahs are exactly the same.
The black "tear marks" running from the corner of its eyes down the sides of the nose to its mouth is to keep sunlight out of its eyes and aid in hunting and seeing long distances. How? Don't ask me. That's what Wikipedia said. Another interesting fact that I discovered after mentioning them purring yesterday was that unlike lions, tigers and leopards, the cheetah can purr as it inhales, but cannot roar. By contrast, the big cats can roar but cannot purr, except while exhaling.