posted on Jan, 21 2008 @ 09:27 AM
Those look EXACTLY like a jpeg 'compression artifact' or 'blocking artifact' caused by lossy jpeg compression. This is caused by the jpeg
compression software attempting to interpolate (basically "guess at") the color of a pixel based on the surrounding pixels. It does this in blocks
of pixels (usually 8x8 blocks), so if for instance that block contains both brown soil and gray sky, the software's "guess" could be inaccurate.
This won't happen with the raw file, nor with a jpeg file saved with 'non-lossy' compression.
If you go to this page on the NASA website: marsrovers.jpl.nasa.gov...
you can find this photo compressed in both formats -- lossy and non-lossy. Scroll down the page until you get to "18-May-2004". You'll see this
photo labeled "Bonneville Crater Panorama". If you download the 39 MB file (I don't think you can view it directly), then zoom in on the hills,
you will see there are no compression artifacts. The file is large, so you probably need a high-speed internet connection (cable, DSL, etc.)
I cropped a part of the hills out of that large photo. These are the same two hills that are "zoomed-in" on the far right of the OP's photo, and
the ones in the OP's example:
[edit on 1/21/2008 by Soylent Green Is People]