for me I can change wallpaper from pic..
like I go to my images folder and on top there is option for set as wallpaper.. since I cant change wallpaper from background showing black screen with 2 options so I used that way to change and I only can do 8 screen if I set 9 screen the 9th screen has bug whatever I put in there the deleted button keep showing on the widget or icons so Im using it 8 screens now