Altered image? no..
Centrosphere,
"If you amplify that region with Paint, youŽll see that the texture of the pixels.."
It appears to me to be a smudge on the optical window covering the camera. A small camera with a wide-field lens at f/8 or more will show smudges on the front optics as hazy areas in the image. Perhaps it got smudged nosing about in the dirt.