Completely stumped in project veronica

Must have a deficient intellect

It's the room which you open with the golden key and you need to press
buttons underneath pictures. I was assuming I needed to press them in a
certain order then go up the steps to the big picure and then press the
button.

But that can't be so because none of the relevant permutations work.

Did you guys complete this game without any help whatsover? It's the first
time in the game I'm completely stumped.