QUOTE (siravan @ Jul 8 2008, 06:42 AM)
I wonder whether you can see the same low-contrast, semi-regular patterning in other MOC wide-angle images.
Here's one of interest, from a simulated view from MRO as it was approaching the Phoenix site the day after the landing:
So there's a bit of the "cloud" effect on the left but not so much elsewhere. Could that be an area where ground ice is subliming and condensing again at height?
Unfortunately there's a bit of a dataset problem around the Phoenix site, approximately at the center of this MGS mosaic:
Looks like some inconsistent lighting on the stitched-together sections. Also, maybe clouds were there for one pass and absent the next? Here is what MRO was looking at just a minute or so later:
Some pretty large clouds? Anyway, there are plenty of different kinds of artifacts (stitching, posterization, dropouts, etc.) but not compression per se, IMO.
Note that the HIRISE field of view is much less than this image (like 1/50th the height).