Unless there's a parallel repository of all the images in a form that's easy to search (some kind of sparse, feature-rich form that's quick CV-match friendly), which isn't the hash, you're going to have a hard time with that initial assessment and enforcement of potential infringers.

That right there could be a pretty expensive system to maintain and it isn't ideal to distributed across a bunch of blockchain participants, it probably has to live in a Kodak server farm somewhere.

But who will determine whether two different images are visually the same?

What’s the point of a decentralized system if a trusted third party decides which images are visually equivalent? Just use that third party to register the image with in the first place, rather than in a blockchain, since that party gets to invalidate your image-hash in the chain anyway (in case your image is deemed visually equivalent to an image earlier in the chain).