Overriding images

[RetroArcade]

I know you can now override some of the user images by placing them in the images folder within the theme. I am trying to find out though what is the name or section of the code in the different xaml that this overrides. Specifically I am trying to figure out the fanart(background)  overrides. For instance take the minimal theme, if you use a fan art image it will display it only within the portion that the video plays. Say I wanted it to display over the whole screen area which code in the theme would have to change in order to define the whole area as background? 

 

Also is there a way for this to be defined over video? Because it seems to only display if videos are unchecked. Is it a case of only static background or video within this area and not both? 

Not sure if this is understandable, if not I'll try to clarify a but more