Adding map images to Mainmenu the correct way?

[Synergy2069]

Does anyone know how or have a tutorial for adding the map preview images to the mainmenu without having them repeat. I think some of the maps are linked so when you inject one image for one map, it adds them to other maps as well. Is there any way around it? Any help would be greatly appreciated. Thanks

Edit: I figured it out. I just made the bitmap dependency in the matg tag point towards my image.