This was my conclusion as well testing the image detectors.
Current automated detection isn’t very reliable. I tried out Optic’s AI or Not , which boasts 95% accuracy, on a small sample of my own images. It correctly labeled those with AI content as AI generated, but it also labeled about 50% of my own stock photo composites I tried as AI generated. If generative AI was not a moving target I would be optimistic such tools could advance and become highly reliable. However, that is not the case and I have doubts this will ever be a reliable solution.
from my article on AI art - https://www.mindprison.cc/p/ai-art-challenges-meaning-in-a-w...