Re copper-bronze-dichroic-film-photo.jpg : if you look at the pixel values of the central section, you’ll see that almost all pixels have zero in the red channel. The data has gone, and no tweaking will recover it.
Of course, we can still guess values for the red channel. Say, the average of the red and green channels, but a bit less at the top (for the blue sky) and a bit more for the bottom (the red road surface).
The tourist photo hasn’t lost as much data. Tweaking reveals the young man’s top is green, and the car is red. But that much tweaking of a JPG creates banding.