I agree that these appear to be produced by humans, but I would be curious why you think you don't know the history. I think if you saw any painting or depiction you would infer a history. But there are cases where you might be wrong. There are certainly natural phenomena that resemble carved figures. There are certainly objects that are argued about.
What is the objective method used to make the determination?
What about the appearance of the face of Jesus or Mary that no one drew on a building, rock etc.? How does Andrew tell whether someone drew those or not?
What about the face of Jesus on that pancake that was sold on Ebay?
"What is the objective method used to make the determination?" Since cavemen drew monkeys, it is obvious they were still there after humans were designed. So, evolution is false.
Well, anything not directly observed about the "painting" would of necessity be inferred.
The fact that you would class it a "painting" infers a judgement on your part.