Please follow these steps:
1. Tap on the “Menu” button at the top-left corner:
2. Tap on the “Settings” button at the top area:
3. Tap on “Wallpapers” cell to open “Wallpapers” screen:
4. Tap on the wallpaper you want, then tap on “Close” button at the top-right corner:
P/S: If you don’t want the wallpapers to be changed every time you change quotes, please turn off “Auto Wallpaper” feature (“Auto Wallpaper” cell) at step 2.