Hi @intothewoodx
I believe what you are trying to do may be accomplished with revolution slider.
In slider settings, set your slider to full screen, in general settings set shuffle to on.
In slides you can add an number of slides each with a different image (effictively your repository)
In timing, set the transition time to something ridiculously long like 1200000 (20 minutes)
In effect, the layer slider will serve a random image that will be on screen longer than your user.
You can add clickable buttons like “enter” to slides as well.
I’ve never actually tried this so I don’t know if it will always start on slide 1 and shuffle from there, in which case set slide 1 to plain black with shortest possible duration (a few milliseconds) and fade of your choice into new random image slide.
Hope it works, no guarantees ๐