Just to sum this up, here’s what I did in the end. What I needed wasn’t really an “image gallery” (as originally mentioned) or a direct way of displaying a PDF file, but a means of displaying one image at a time and allowing the player or game to choose which one.
- Converted the six-page PDF file to six PNG images using PDFill PDF Tools.
- Reduced them in size to 608x860, using GIMP, the same height as the map in Counterfeit Monkey.
- Used Simple Graphical Window by Emily Short to display one image at a time.
- Needed a couple of extra lines as a temporary fix to that extension.
- After “releasing” the game from Inform 7, used blorbtool.py to ensure that Quixe can display the images when the game is played online.
You can see the final result in Daddy’s Birthday – just type “walkthrough” to see (what was) the PDF. Thanks for your help.