[monkapotamus]

Is this what you mean?

http://mars-news.de/color/blue.html

Pic. A, Viking 1, Nr. 12b069, 29. August 1976, 12.65 locale Mars time This picture was created with color-correction derived from the filter response data.  (click on picture to view it in original size) All Viking and Pathfinder images courtesy of JPL/NASA/Caltech.

original data without correction

[monkapotamus]

I don't know what these surface features are (images from Mars Global Surveyor) but they are interesting:

http://ida.wr.usgs.gov/html/m08046/m0804688.html