- Entertainment. Since you can create screen savers from the photos in your iPhoto Library, your Mac can serve as a digital photo frame when you aren't using it.
- Security. You can require a password be entered when the screen saver ends.
- Go to System Preferences on the Dock or from the Apple Menu.
- Go to the Desktop & Screen Saver pane.
- Go to the Screen Saver Tab.
- Select a screen Saver from the list. Screen savers are grouped by Apple-supplied displays and photo displays. Photo screen savers contain a few stock photo sets and then access to all of your iPhoto assets.
- Select a number of minutes of inactivity before the screen saver will start.
The Hot Corners... button will let you choose a corner of your screen that you can drag your mouse pointer to to start the screen saver immediately.