Phobos seen from the Martian surface, Curiosity sol 45 (September 21, 2012)
Just after sunset local solar time, Curiosity turned its narrow-angle Mastcam-100 toward the sky to image a crescent Phobos. This version is a slightly processed version of a raw image (blemishes and hot pixels have been cleaned up); it will likely be replaced later with an official release.
Here is a zoomed-in version:
This image is in the public domain.
Original image data dated on or about September 21, 2012