One thing you could do is have the camera hardware sign the raw image, then make a zero knowledge proof that says original photo was signed by real hardware, an

One thing you could do is have the camera hardware sign the raw image, then make a zero knowledge proof that says original photo was signed by real hardware, and then the only edits applied to it were simple things like cropping, changing colors etc Seems reasonable to coordinate the updates with a blockchain (though not necessary for use cases where you trust the platform / coordinating entity). Disclaimer I work at a zkSNARK / blockchain company :)