The real question is "Who is the author?"
Because actually the user isn't. The AI is. AI's don't have a right to copyright. You making a few lines and the AI making the actual image does not make you the creator of the image.
Because actually the user isn't. The AI is. AI's don't have a right to copyright. You making a few lines and the AI making the actual image does not make you the creator of the image.
For algorithmic art, likewise the developers of the software typically provide permissive licenses to the users of the software.
AI makes this harder because the works are massively derivative works, which AFAIK, do not have much precedants in law. The question is not easy to answer unless the author (Nvidia in this case) owned copyright over all training data.