[Retros] François Le Lionnais picture

[Eric Angelini]

Hello Retro-fans,
This is another kind of retro-analysis I'm looking for ;-)
The hereunder link shows a 1936 picture of François Le Lionnais.
He stares at a game of chess. Or at a chess problem? Friends
of mine have tried to rebuild the position. I quickly proposed
my vision of it (link) and my explanation :
http://www.cetteadressecomportecinquantesignes.com/FLL.htm

... but someone claims now that "there is a pawn on c6 -- look
at the shadow on d6!") -- so I'm confused... Could you guys ex-
plain at what exactly is FLL looking? Does this diagram ring a
bell to someone?

Best,
É.