I would sample a few dozens equally space pixels out of the frame, then drop similar value frames, and send that with timestamp. In the cloud, you runs those few pixels in a content recognition model.
It doesn't have to be especially accurate or know any niche content, the point is to make a psychomarketing profile of the customer like "car guy, watches tool reviews".
I don't understand why you believe I ever gave the slightest consideration to which servers my messages transit through when posting on Lemmy or that it says anything about beyond the 20 seconds it took to pick a server out of a list years ago.
But I do recognize the hostile attitude that does believe it would matter. I will give you an example. In france, car plates are issued by "departments" which are minor administrative regions in the country.
When various busybodies and roadragers encounter conflicts on the road, they look at the other car's plate and whenever that plate is issued by a departement other than their own, they invent idiotic and derogatory narratives that explain why "I am right and they are wrong" based on that stupid little story they tell themselves.
I can only imagine you are doing that with... Server hostnames ? Which might just be saddest terminally online behaviour I have ever observed on Lemmy, good job.