If you look at the shadows, you can tell that the sun must be almost straight up... or slightly further away from the camera...
If you look at the shadows on the "person," they exactly match how, a person at that time of day, would have shadows. One in the armpit. One along the leg, showing that the "gloved hand" is actually above it, and one under the butt, showing that it's blocking out sun.
So even if it is a rock, it is in the shape we are seeing.
the only strange thing seems to be the scale... but you'd have to see the full scale image to see how miniscule it is. It's almost behind the rover really... but if you follow the ridge in the main picture, you can see that if these were people, they would be at the bottom of a steep ridge which then slopes up slightly into the rocky out cropping they seem to be hiding behind.
I say they because if you look in the pic I posted, there looks to be 3.
One poking its head up between rocks like a Jawa on the left, the one walking in the middle, and one that's leaning over an outcroping just right of it... in a stance that almost is similar to someone with a gun... with something protruding back over the ledge... which is casting a shadow correctly btw... and seems to be the same color as the "glove" of the one walking...
yeaa......
I need to stop analyzing this and go to bed lol