The article I linked in my other comment goes into detail how, based on NASA's own color guide which is mounted on the rover's chassis in view of it's camera, their images of Mars appear to be deliberately tinted (in the early days orange-red; lately yellow-green).
The author, who is a camera specialist and was also involved in the field of color correction and chemistry in the film-world for years, shows how when the colors are corrected in photoshop; based on the manufacturers specifications of that color guide, available knowledge of NASA cameras, and another lines of inquiry; the result is usually like the first image on the left; terrestrial looking with a hazy blue sky.
The article I linked in my other comment goes into detail how, based on NASA's own color guide which is mounted on the rover's chassis in view of it's camera, their images of Mars appear to be deliberately tinted (in the early days orange-red; lately yellow-green).
The author, who is a camera specialist and was also involved in the field of color correction and chemistry in the film-world for years, shows how when the colors are corrected in photoshop; based on the manufacturers specifications of that color guide, available knowledge of NASA cameras, and another lines of inquiry; the result is usually like the first image on the left; terrestrial looking with a hazy blue sky.