Nope, not possible for humans 10,000 years ago to imagine what is depicted. They might have made up reasons for the things they saw/experienced, but the pictograms illustrate technology, not magic.
Yep. Stylized drawings are not evidence of aliens.
It’s the people now alive who are doing the imagining. Like seeing the man in the moon, or the face on Mars.
It’s what humans do. See patterns, some there, some not there.