Welcome to the thread!
To get the private photoshoot, you not only have to be on the D-only path in 0.19, you pretty much have to have been so all along.
For instance : you have to reject Georgina, AND Georgina has to have the blackmail audio tape ; you have to have received the extra severance pay ; you have to have purchased a membership in Cassandra's photo studio, and she's given you the outfits for D to wear in the photoshoot ; then in 0.19, choose the yellow earrings, choose Stump 1 , choose "No, it's perfect" after D puts on the yellow gown. ONLY after all that do you get the private photoshoot.
If you do not wish to do all that, find a save in this thread to take as a shortcut. I'd recommend the one by
@wrx21 on page 1148 (14-1). That would put you at the end of 0.18, about to start 0.19, on the correct path. I'm no techie, so please refer any questions about such saves to whoever the donor is.
Good luck!