Static Image over Page/Section/Slides

I am trying to lay a static image over a set of slides and/or section. I’ve spent the whole weekend messing with the existing divs and adding my own, but it has been an exercise in futility.

This functionality is present in the examples page (http://wp-fullpage.juzed.fr/), so I assume it CAN be done. I just can’t figure out how!

https://ww.wp.xz.cn/plugins/wp-fullpage/