In the above image with a 200% zoom factor, view of the "cricket" on the left and the tiny white spot in the right frame. Next to the upper left of the white spot is a few .jpeg compression artifacts. It appears to me that something likely has been removed from this spot and the empty pixels are a carelessly left behind manifestation of this intrusion.
You see the rover imaging, although the camera work was promoted before launch as some of the best resolution ever utilized, as released to us it is in the .jpeg format and severely compressed. That kind of severe compression results in smaller display image file size but also very poor image resolution quality. In other words, what ever was gained by sharp high definition camera work resolution in taking the pictures is lost and severely compromised in the public image release presentation. This obviously prevents effective zoom and closer examination of evidence like this. Now it's hard not to contemplate how convenient that is should secrecy be someone's goal.

It demonstrates some kind of vegetation or lichen growth especially prominent on one of the rocks so that just enough detail of it can be seen and recognized. --This original dark blue false color of the evidence brings up a point. As most of you know the real true color of living objects frequently gives them away as far as the human eye being able to identify such evidence is concerned. For example, much of vegetative life is a green color for reasons most of you are familiar with. On the other hand, lichen life for example works on a little different symbiotic principle often demonstrating fairly strong yellows, browns, grays, and even reds. The official position would have us believe that the rover imaging is only in black and white and not in color and that they know what kind of false color to add to an image. If you really completely believe that, I have a large bridge that I would like to sell you at a bargain price.