Lan Fleming has made a fairly good job of replicating how this de-enhancement was done. Embossing is not an enhancement technique. Moreover, the new image was poorly suited for showing whether the facial features seen in the Viking pictures stood up under higher resolution or whether there were any constructional features in evidence. The image was not taken directly from above, but at a 45 degree angle to the Martian surface from the West. This meant that we were actually seeing the facial features in semi-profile.
Faces look at their most face-like with the light coming down from the top of the head.
In fact the image was not greatly superior to that taken by Viking. The image was taken through what was effectively a Martian dust storm. This together with the low resolution meant that it was highly unlikely that it would be possible to see any evidence of structural engineering if it existed. This page is now becoming rather image intensive.