I like this because they are trying to show how AI is a copyright laundry.
I can see other commenters picking apart its method of heuristically guessing at source images from training data. That obviously won't be accurate, or a full picture, but I wonder if it would convince a judge.
An interesting challenge for these heuristics would be to take the picture under test along with its prompt, retrain the model without the training pictures it identifies, and regenerate using the same prompt to see whether the output is remotely similar.
Obviously that would be hilariously expensive and slow for a casual web service like this, but not beyond the realms of possibility for a wealthy copyright-holder.
e.g. if an prompt for an image includes "in the style of Kincade", and you could subtract all of Kinkade's copyrighted images from the training data, would the model still be able to produce anything like his work? If not, Thomas Kinkade might have a copyright case against people who publish AI art "in the style of Kincade", because he could show that his input was the major contributor to any lucrative output, even if nobody could pin down the cause & effect.