My daughter's a little artist too. She has a very good visual memory as well. She also has a weird ability to project 3D images from her mind into the real world - she's knows it's actually still in her mind. She has a few future careers in mind, but she often speaks about being a book illustrator, which I don't think would be out of her reach.
I would nurture this, if I were you, which you are obviously doing anyway. It seems like he could be an animator.
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"We act as though comfort and luxury were the chief requirements of life, when all we need to make us really happy is something to be enthusiatic about." Charles Kingsley