Hi Jay hope you are well. The problem I had was when I made the background opacity set at .05 and that allowed me to have the centre of the screen see through to allow the background picture to show behind. however when I set a room picture it would show the pic in the centre but also a white background right across the top half of the screen. The way I got round it was to set the background colour on the display tab in the game section to transparent and that sorted it out.see below a screen capture.
as opposed to this
Thats what the problem was hope it makes sense

Happy Adventuring

PS ignore the second picture and please don't ask