You could publish the results of your classifications as NIP-32 labels tagging the image hashes directly and let clients subscribe to those.

I think nos.social is doing something similar, so we almost have a protocol already. nostr:npub16zsllwrkrwt5emz2805vhjewj6nsjrw0ge0latyrn2jv5gxf5k0q5l92l7 nostr:npub1wmr34t36fy03m8hvgl96zl3znndyzyaqhwmwdtshwmtkg03fetaqhjg240