> Yes but the idea is that you trust the camera which unique and works as a physical private key.

You're pushing a (bad) technical solution to a social problem.

Cameras that cryptographically sign their output will not solve anything. The idea has more flaws than it's possible to list, but here's a big one: do you really think a technological gimmick like that would stand up to a nation state? Do you really think the CIA, NSA, FSB, Chinese Ministry of State Security, etc. will not be able to sign whatever the hell image they want with a camera's signature?