Mac Wallpaper vs Screen Saver: What Is the Difference?
Your wallpaper is the background behind the desktop while you work. A screen saver appears after your Mac has been idle, according to your settings. The lock screen is the screen you see when access to your Mac is locked. Their appearance can be related, but they serve different purposes.
Change the desktop wallpaper
Open System Settings → Wallpaper and choose an image, color, or one of Apple’s collections. To use a saved picture, choose Add Photo → Choose File under Your Photos. A still picture remains a still desktop background.
Change the screen saver
In current macOS, open System Settings → Wallpaper → Screen Saver, select Custom, and choose a screen saver. Options vary by selection. Some aerial wallpapers can also be used as slow-motion screen savers. Apple documents the available choices in its screen saver guide.
Use your own photos as a screen saver
In Screen Saver settings, select Custom, then under Other choose Photos → Options. Choose a folder or photo library and confirm your selection. See Apple’s photo screen saver steps. Check Lock Screen settings for when the screen saver starts and when a password is required.
Why does a different picture appear when I lock my Mac?
The selected screen saver, wallpaper, and lock screen behavior can differ by macOS version and the type of wallpaper. Review Wallpaper and Screen Saver settings separately. If you use multiple spaces, also check which desktop and display are active.
To change the picture behind your apps, see how to set a Mac wallpaper.