Hi Jeremy,
Sorry! Jeremy we are not misleading it we have used in the demos are purely for demonstration purposes, and are used to give the visitor a functional preview of what the theme will look like once content has been added. By the way we have attached it in previous version of the theme but according to WordPress.org policy Revolution Slider Plugin has been removed because of non GPL code.
Also the another main reason to remove it was that our customer are having difficulty to have a good support and auto update feature for the plugin.
Anyways it seems that you have set the Slider Revolution Plugin in your site.
To make the image stick first go to the main slide settings and set the background image for the individual slide and set the background fit option to cover and background position option to center center as shown in this screenshot.
Also if you have purchased the Slider Revolution you will now get dedicated support from main author here and also you will get auto update feature too.
Thank you!