[Reily]

All it takes imaging element misfire, turn off, response start to decay, etc. I’ve seen sensitive earth located images have a dead pixel due to a cosmic ray.

[KamperKen]

"All it takes imaging element misfire, turn off, response start to decay, etc. I’ve seen sensitive earth located images have a dead pixel due to a cosmic ray.

Correct, a point I did not dispute in my post. My point was that the possible artifacts are not random. If they were random we would see bright spots on things like the rover itself which is often in the foreground. The bright spots are in locations where it's possible for something physical to exist.