Funnily enough, the image doesn’t look anything near as convincing in negative…


So I did a bit of enhancement and It looks to me a lot like the ‘arm’ is in fact a shadow on the terrain in the background that has been superimposed onto a nondescript foreground rock by chance.
The colour make-up of the ‘wrist/hand’ is consistent with the background, but different from the ‘arm/shoulder’ area, which more resembles the rest of the body.
Or perhaps the martian is just wearing a green dress…
