AIs might not know much about art, but they can easily tell apart one style from the other — even when they’re terribly similar.
Identifying forgeries is hard, time-consuming, and expensive, but we need it more than ever. The art world is full of forgeries. Recently, a supposed Da Vinci painting sold for $450 million, although suspicions loomed that it might be a fake. The problem is, humans have a hard time telling apart real art from fakes. In most cases, a trained eye will catch small details, identifying tells that confirm or infirm authenticity.
If you want a more thorough confirmation, you might take the art piece in a laboratory for infrared spectroscopy, radiometric dating, gas chromatography, or a combination of such tests. All this takes a lot of time, money, and effort.