With photos, I could see a cryptographic solution. Of course it would still need some kind of centralized trust, but it's doable if people cared enough. It could be applied by cameras themselves.
This is already a thing. Leica cryptographically signs images. Useful for establishing trust for photojournalists I guess. I’m not sure how deep the chain goes. Do they have hardware attention down to the sensor? You could take a picture of a screen, but that would likely have some other tell-tales. Especially if Leica took another step like putting a depth sensor in the package and added its data to the signature.