This is a small tutorial to change the view of wallpaper style in .theme file. This will be very useful if you are creating a unattended windows installation. By default you can change this settings via personalization. Ok here we go,

* Open a .theme file and find the following section in that

[Control Panel\Desktop]
Wallpaper=%WinDir%\Web\Wallpaper\Windows\img0.jpg
TileWallpaper=0
WallpaperStyle=10
Pattern=

* You need to edit TileWallpaper and WallpaperStyle values to change the view of wallpaper
* Following are the values for respective wallpaper views. You have to put the following values in "WallpaperStyle"

10- Fill
4,5,1 - Center
2 - Stretch
6 - Fit

Fill:

[Control Panel\Desktop]
Wallpaper=%WinDir%\Web\Wallpaper\Windows\img0.jpg
TileWallpaper=0
WallpaperStyle=10
Pattern=

Center:

[Control Panel\Desktop]
Wallpaper=%WinDir%\Web\Wallpaper\Windows\img0.jpg
TileWallpaper=0
WallpaperStyle=4 (or) 5 (or) 1
Pattern=

Stretch:

[Control Panel\Desktop]
Wallpaper=%WinDir%\Web\Wallpaper\Windows\img0.jpg
TileWallpaper=0
WallpaperStyle=2
Pattern=

Fit:

[Control Panel\Desktop]
Wallpaper=%WinDir%\Web\Wallpaper\Windows\img0.jpg
TileWallpaper=0
WallpaperStyle=6
Pattern=


Tile:

[Control Panel\Desktop]
Wallpaper=%WinDir%\Web\Wallpaper\Windows\img0.jpg
TileWallpaper=1
WallpaperStyle=10 (or) 6 (or) 2 (or) 4
Pattern=