Open the Settings app
Tap Wallpaper
Tap Choose a New Wallpaper
Tap a wallpaper option (Dynamic, Stills, or Live Photos)
Select the wallpaper image you want to remove
Tap the current wallpaper preview
Tap the Set button
Choose Set to Home Screen, Set to Lock Screen, or Set Both
If you want to revert to Apple’s default wallpaper, repeat the steps and select a default wallpaper from the available options
To remove a custom wallpaper, select a different wallpaper from the options and set it to the same screen(s)