I think the line is sightly fussier in the United States. https://www.justice.gov/criminal-ceos/citizens-guide-us-fede...

>Visual depictions include photographs, videos, digital or computer generated images indistinguishable from an actual minor, and images created, adapted, or modified, but appear to depict an identifiable, actual minor

I am not a lawyer, but given that language it gives the impression that even art may fall under the scope of U.S. law. Am I correct? Possibly not, however that ambiguity will cause many to avoid crossing the implied law to ensure they don't break the actual law.