Time to speculate on computer psychology.

The AI seems to have performed a free-association game. "Yves Klein" in the realm of visual art means "very super blue." "Very super blue" in the context of MLP—especially among the pantheon of ponies most likely to be immortalized in stained glass—is an obvious (horse) shoo-in for Her Royal Horse Princess Luna. However, the computer didn't fully connect that final step (though it seems to have drawn an alicorn in the neutral evil slot).