NASA's images of the Earth and the moon were processed separately and then combined
The images were captured on Nov. 20, 2016 by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. At the time, Mars was about 127 million miles from Earth.
Both images were processed separately and then combined due to the difference in the brightness of both bodies. “The moon is much darker than Earth and would barely be visible at the same brightness scale as Earth,” NASA said.
The image still reflects the correct size and positions of both bodies.