I needed to figure out a simple way to set the default background image. I didn’t want to force the background image, I didn’t want to apply a GPO, and I wasn’t having much luck editing the default user hive. I happen to stumble onto this solution by chance, really. So into regedit we go for this.
The location I am looking for is:
You may need to add keys, but in general you want the below keys to be set. I set DesktopBackground, but excluded it in this example because it contained a path I didn’t want to post. This is just a hex string that contains the full path to a file using the oobe folder is recommended. The oobe folder may not exist on your system, so go ahead and create it if needed.
Using this plus other OOBE branding, I was able to make a bat file which upon running completely sets up branding on the System Information panel, theme and default background.