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.
Yeah, from my POV that's a feature. If a process modifies your photo, its no longer your photo and shouldn't be able to masquerade as your photo.
Obv, integrating GPG w OpenCamera is just an example. GPG could be integrated w social media apps so that after you select "share," and the image is processed, that modified image is signed before upload.