In the System Preferences window, select Desktop & Screen Saver.
In the window that opens, go to the Screen Saver tab.
In the left pane, select a screensaver style.
In the right pane, open the Source drop-down list.
In the Source list, select the source of the screensaver images. In this example, I have selected the Photo Library. You can select from macOS presets or your own photos.
