Is the image on the left supposed to be from Viking? If not from where does that one originate? No citation is made for the image that I could readily find.
It should be noted that the best resolution for Viking was about 40 meters per pixel. With the estimated size of the tetrahedron at 290 meters 5.84 meters per pixel in the MGS image, that would mean the Tet was a huge 8 pixels in any available Viking image.
I did a search of the Viking archives and while the area in Candor Chasma is well imaged there is none available of the Tet itself.
Please clear up the descriptions and origins of these two images on page 306 of Wil Fausts tetrahedron.