alph2z
If the area in the center of the image were modified it would show up as a noisier area compared to the surrounding.
Having tweaked it a bit with image processing software, I second the opinion about this picture probably not having been altered. Actually, the first time I looked at it, my impression was that the different aspect of the center area resulted from the sand/mud having been flushed by the blast of the ROV's propeller(s) or turbine(s).
auv-ee will possibly have some interesting comments, especially regarding the altitude at which the ROV operates above the seafloor, and the suspected "washing effect" of the propellers ?