Nathan is right though. It specifies a Habsburg jaw, not that the frog is a Habsburg king/prince. It's understandable that the LLM will hallucinate a king from this, but it isn't what's being asked of it.
When I ask to create an image of a smartphone, it will most likely show the front and while it's turned on, even though it's not mentioned. For a person, it will add clothing.
Adding things that are not explicitly stated in the prompt but that are probable are the main benefit of AI, as far as I am concerned.
I'm afraid you'll need to look up "frog prince" yourself. It was fictional.
Not sure what the argument here is. I expect AI to consider fictional entities if they are semantically connected to the prompt.
It's not hallucination. The prompt lacks details and given that an AI or a human has some artistic freedom. After all, that is why current AI is usable at all.
An artist given the same prompt would likely do something similar.