At a guess the posters were used in an early version of the game (possibly a beta) but were replaced in the latest version. However, the developers didn't remove the images from the images folder.

In VF1 I once found what was presumably an abandoned puzzle; there were two images of a wooden chair, broken and complete, that went on the deck. It never appeared in the release versions but could be seen in a 'sneak peek' video shot by LDW.