These photos actually belong to the really bad ideas within the film. They look cheap, printed out by some assistant - as if Blofeld got this idea at the last minute, scrambling to find them on the internet. "I want these on the wall, got it? Okay, do the explosives first. But then the pictures! They really will rub it in, when James is overpowering you and finding the correct way to me... in a huge building that has hundreds of rooms and barely any working lighting anymore."
I do like the idea of tieing the previous Craig-era schemes into Blofeld´s organization - but this is so amateurishly done with these pictures (and the obviously totally easy to decode-imprints on the members´ rings which work as a kind of USB-stick containing every wrongdoing and wrongdoers because... the members so easily forget? They want to always be able to look up who is their partner-in-crime? Or are they trying to make it easier for the police to offer them a witness protection program, giving them all the data upfront?
Another proof how half-baked ideas were forced into the narrative.
Blofeld had an assistant in London who would have access to everything, and more than just a photocopier - namely, his chief of intelligence, M's "new best friend", Max Denbigh. So getting the pictures on the walls, and access to the old building, wouldn't have been a problem, I imagine. Of course, "I imagine" is what we're forced to do as an audience because much in the final act is never explained.
Also the pictures could have been on the walls for some time. Maybe Blofeld and Denbigh spent some time together in the old building putting up photos and plotting 007's downfall?