I get what you're going for but this would absolutely wreck privacy. And depending on how those signatures are created, someone could create a virtual camera that would sign images and then we would be back to square one.

I don't have a better idea though.

No signature or verification, no trust

And the people that are going to check for a digital signature in the first place, THEN check that the signature emanates from a trusted key, then, eventually, check who's deciding the list of trusted keys… those people, where are they?

Because the lack of trust, validation, verification, and more generally the lack of any credibility hasn't stopped anything from spreading like a dumpster fire in a field full of dumpsters doused in gasoline. Part of my job is providing digital signature tools and creating "trusted" data (I'm not in sales, obviously), and the main issue is that nobody checks anything, even when faced with liability, even when they actually pay for an off the shelve solution to do so. And I'm talking about people that should care, not even the general public.

There are a lot of steps before "digitally signing everything" even get on people's radar. For now, a green checkmark anywhere is enough to convince anyone, sadly.

The problem is that "AI" doesn't actually exist. For example, Photoshop has features that are called "AI". Should every designer be forced to label their work if they use some "AI" tool.

This is a problem with making violent laws based on meaningless language.