The screen saver, a series of images that appear on your screen once it goes to sleep, can add a little bit of design to your sleep screen instead of your typical black screen. You can change what images appear and how they appear.
Photos is the default app for importing photos and videos into a library stored on your Mac. But there is another app in your "Applications" folder of your Mac that most people overlook called Image Capture. Unlike Photos, Image Capture imports your photos and videos to the folder of your choice. This is a great option to use if your importing pictures to share or if your a WindowsOS user because Photos libraries cannot be opened in WindowsOS.