These are the paintings that the "prieure documents" say Berenger Sauniere went to view when he travelled to the Louvre in Paris: a painting by Poussin of the Shepherds of Arcadia (at the time he could have visited, the 2nd version would have been present), a depiction by Teniers of the Temptation of St. Anthony (my research suggests the 1st version would have been the one on display in the museum at the time), and an anonymous portrait of the Investiture of Pope Celestine V. The final painting below, Teniers' St. Anthony and St. Paul in the Desert, is said to be the "correct" Teniers because it shows the saint NOT being tempted. Alas, while Henry Lincoln says it could be found at Shugborough Hall, it has never been in the Louvre.
Incidentally, I admit it remains an unproven assertion that Sauniere ever did visit the Louvre, either in 1892 or 1913. The reason I post these pictures is that, whether or not he ever did visit the museum, the authors of the "prieure documents" are clearly calling attention to them. For whatever reason.
The yellow line indicates overlap between the two geometries.
Neither John nor I are sure whether this geometry has anything to do with the real world, but I felt the need to present it. John went further to create an 18-point star from the 6-point star -- if you want to see this further construction, you can email him.
Red lines are the pentagram, black the hexagram, blue lines of sight/staves, yellow "control lines". For this diagram, I take all blame or credit, but still must thank John for giving me the inspiration.
Yellow lines mark the pentagram Lincoln showed at the end of Holy Place ; red lines another symbol which I think is interesting; blue hints of a hexagonal geometry on the other side centered on the face of Magdalen; and light blue highlighting the black sun and blue rose, the latter being a key Symbolist icon.

Notice that this is an inversion of Poussin's original work, whether deliberately or accidentally.
Please note that I consider this page a "work in progress". The images from which these geometries were generated were of low quality, and possibly off parallax and off scale. I also make no claims of significance about their existence, only that it does appear to suggest something about the design intentions of the artist.