Find photo album
Find the "photo album" icon on Huawei's mobile phone desktop.
Select a picture.
Then find the picture you want to set as the lock screen wallpaper in the opened album page.
Click more
Click to open the photo on your phone, and then click the "More" button in the lower right corner.
Set the lock screen wallpaper
In the pop-up photo more menu, click the menu item "Lock screen wallpaper".