[GAME/SNAP] is the snapshot. width and height are just random numbers. wiiflow sets those. and the texture is of course set by wiiflow. the x and y are the upper left and the only thing to worry about.
[GAME/OVERLAY] is the snapshot overlay for handhelds. same info as [GAME/SNAP]
[GAME/SNAP_BG] is used for 2 things.
1. the dimensions of the window inside the frame. (x,y,width,height) used so wiiflow can center the snapshot.
2. the texture of the window inside the frame. wiiflow has it set to a transparent image. but you can make and use a solid colored image if you like.
the frame is still [GAME/USER4]