4 of 7Image
Here we show the original image grabbed from NASA.gov — showing that it must be real.
Zoom in a bit and you can get the first glimpse of the rat/squirrel on the left.
Here's a comparison of the acutal photo that's being spread across the Internet (above) and a 7X enlargement (below) that I took from an older version of Photoshop. Looks real, anyway.