load them with the mega bezel shader
basicly you could save a mega bezel preset you want to use under a name in retroarch and edit the slangp file ^^
you have to search for “BackgroundImage” or “BackgroundVertImage” for games with vertical screens and than edit the file path
like this BackgroundImage = “Mega_Bezel_Packs/P3sT/overlays/overlay.png”
this is the folder structure i will use in the future cuz i will also include presets for all in the next update i think like i said at this point there are just the png files ^^