Eventually, we will just have to accept that photographic proof is no longer proof.
There are ways that you could guarantee an image is valid. You would need a hardware security module inside the camera, which signs a hash of the picture with its own built-in security key that can't be extracted and a serial number that it generates. That can prove that an image came from a particular camera, and if you change even one pixel of that image the signature won't match anymore. I don't see this happening anytime soon. Not mainstream at least. There are one or two camera manufacturers that offer this as a feature, but it's not on things like surveillance cameras or cell phones nor will it be anytime soon.
This, exactly this. The fact that they would even consider this rules them out for me forever.