Ok, I think it’s probably working properly, in the base POTATO presets both a horizontal and vertical image are supplied, because they have to be because the bezel & frame are baked in to the images.
So since the image is defined in the base preset, to the shader it’s the same as if it was supplied in your simple preset, so if you want it to be overridden then you will need to supply the BackgroundVertImage in your preset.
The presets which are not POTATO do not have the BackgroundVertImage supplied (they have the pass through image supplied). So these should fall back to the horizontal image.






















