Just like https certificate authorities, the only way to fight all the AI slop will be "trusted" camera firmware that signs every image with a full chain of trust that the output was a real physical video taken will a real device at a real location.
In order for this to work, the private key used for signing has to be on the camera, and would have to be kept secret from the camera's owner. This is not possible. You can make it more difficult, use all sort of tricks to hide the key, but in the end, once somebody knows how you hide the key on their device, they'll always be able to find it. And once they have found the key, they can sign whatever false picture they want.