Aw, thank you. I took the picture myself and clipped it for size.
I actually have had ideas for a Master Emerald background banner that can be used all-year-round (other than promotions or seasonal), but I couldn't make it because I had no means to keep the camera fixed in one place while changing the time of day of the map.
Luckily (after 11 months) Jehtt themselves responded to my old reply on how to change time of day in Adventure Fields so I'm hoping I can make the banner in mind soon.
Given December is just a month away, there's always my IceCap banners from last year.