
If you have more than one photo library on your Mac, be sure that the correct one is designated as the System Photo Library. You can sync your device only with the System Photo Library. Use iCloud Photos so that Live Photos keep their effect, no matter what device you use.

Live Photos keep their effect when you import them to Photos in OS X El Capitan and later, but they lose their effect if you sync them back to your device via your computer. When you use iCloud Photos, Slo-Mo and Time-Lapse videos keep their effects. You must import Slo-Mo and Time-Lapse videos through the Photos app or Image Capture in OS X Yosemite or later for their effect to be synced via the Finder. If syncing doesn't start automatically, click the Sync button.

Choose between syncing all your photos and albums or only selected albums.Select the checkbox next to Sync photos to your device from, then select Photos or a folder on your Mac.Click the Photos tab below your device's information.With the first mode, you can conveniently preview images and compare them side-by-side. Your device appears in the sidebar of the Finder window. The best duplicate photo finder for Mac provides three preview modes.Open a Finder window and connect your device to your computer using a USB cable.Each time that you sync your iOS device with your computer, the photos and videos on your iOS device update to match the albums on your computer. If you have photos on your iPhone, iPad, or iPod touch that aren't on your computer, learn how to import them.

You can use the Finder on your Mac to sync photos to your iPhone, iPad, or iPod touch from the Photos app, or from a folder on your computer.
