Cameras designed for this purpose can mitigate the issue, but "solving" it is not easy. Cameras can digitally sign photos to authenticate provenance. You can

Cameras designed for this purpose can mitigate the issue, but "solving" it is not easy. Cameras can digitally sign photos to authenticate provenance. You can add timestamps and GPS coordinates to the signature, though you may be able to subvert those with enough effort. You still need to trust that whoever held the camera when it took the photo was pointing it at an actual event, not at a screen.