Yes - the video / thumbnails to be removed can be hashed in various ways. The hashes can be made public.

A court can order videos or thumbnails matching the hash to be removed, and levy penalties against anyone still hosting them after a period of time.

It’s a less complex problem than policing use of copyrighted music on YouTube videos, and that has been achieved.

How will the sites in question learn of that court order? YouTube is one centralized site, that's different to the internet as a whole.

The hashes would be stored somewhere central.

Sites would be motivated to check it regularly to avoid being out of compliance.

That assumes all thumbnails or pictures hash to the same value. Why would that be? There can be different algorithms, resolutions, crops... And there can be millions of thumbnails to check.

> That assumes all thumbnails or pictures hash to the same value.

The same set of values, yes.

> Why would that be? There can be different algorithms, resolutions, crops...

Yes, so you do normalization and reduction before computing the hashes.

And ‘hashes’ doesn’t have to mean literal SHA. Any non-reversible fingerprinting algorithm will do.

Yeah it's a gnarly problem for sure. I mean I'm sure doing some sort of hash-based blocking would knock out 80% of the content related to a takedown request, but I could also see that last 20% being difficult af to purge.

the internet definitely remembers forever, unfortunately, especially porn