I was not aware of this thread, but now I have found it here goes.
First of all, let me say that if you are interested in the HiRISE images (I am
), you should download IAS Viewer; it allows you to see the images
without having to download them all, it works more or less like Google Earth, downloading only the area that you are seeing and only to the resolution
you have selected.
I think you have to register on the ITT website to download IAS Viewer, and I don't know if I am allowed to post a direct download link (which I have
The images seen at full resolution show much more than the browse versions you used.
It took me some time to find some of the exact spots on the images, if I am wrong just say it.
In this first photo I do not see anything unusual.
In the Valles Marineris crater, I think that the "square ejecta" are only dunes. Unfortunately, this image has some noise.
The Hale crater image is a bit strange, but it looks natural.
The straight sides on the second Hellas region photo look more natural in the higher resolution image.
The south pole image does not look like ruins, at least in this version of the image.
As this image has much noise, I decided to use the red channel version, it suffers less from the noise.
The full resolution images for the last two images that you posted show the difference it may make seeing the full resolution, lossless compressed
image or just a smaller, compressed with data loss image.
I think that the crater is just an old crater, but I am not an specialist,
it may not even be a crater.