How to change the SMS background of OPPOr9

Hello, this is the system default setting and cannot be changed? .

How to change the desktop background picture/wallpaper for oppo r9:

1. Enter the photo album-find the photo that needs to be set as desktop-set as wallpaper-click in and you will see three options: Lock screen wallpaper, Desktop wallpaper and Set at the same time. Just choose one according to your needs.

2. Enter the photo album-find the photo that needs to be set as the desktop-three dots in the upper right corner-set the photo as-wallpaper (non-ColorOS version).