When you bring up the view options to insert a pic for the background of a folder under global, it will apply that pic to the currently open finder folder.
However, when you open a new finder folder/window (whatever the correct terminology is), it's window setting comes up with overrides. You can select view options and then go to the window tab. There you can select to use global settings and the pic will be inserted.
Here's the rub, the originally opened window will display the background entered in the global tab immediately, but when you close it and reopen it, it will use it's default window settings which more then likely don't have the use global settings selected.
Now, if that made any sense, then it's a miracle. Hopefully you can weed out what I'm getting at.