That does seem to be what the page is implying at first glance; though the images clearly show features not visible in the raw photos, so it can't be the case. I'm guessing that paragraph is actually referring to the 'overhead' image [0] next to the one in question, since it mentions how the remapped perspective makes the uniform shadows apparent.

[0] http://mentallandscape.com/C_Venera13_Overview.jpg