To combine Photos libraries, open the source library and export the photos and videos that you want to keep. Then open the destination library (the one that you want to use as your main library) and import the photos and videos.

Select Mac A’s library in your libraries in the list on the left; in the list on the right, select Mac B’s library. Click on Continue, and wait while the software copies Mac A’s photos onto Mac B. Dec 04, 2016 you're essentially making a copy of the one large Photos library file instead of syncing individual photos that have changed. Click to expand. Perhaps you worded that incorrectly with rsync it will only copy over the changes made in that large library file to make it identical, if that is what the OP means not the individual files contained in it. Oct 25, 2019  Launch Photos on your Mac. Click on Photos in the sidebar, under the Library section. Pick out the photos you want to add to an album, either new or existing. Hold down the command key on your Mac and click to select multiple photos.

Choose a photo library

Here's how to open one of the multiple photo libraries that you might have on your Mac or on a connected external drive:

1. Press and hold the Option key as you open the Photos app.
2. Select the library that you want to open, then click Choose Library.

Photos uses this library until you open a different one using the same steps.

Export photos and videos from the source library

Open the source library, then decide whether you want to export your files as unmodified originals or edited versions:

Edited versions retain their edits when you import them. The advantage is that you don't have to recreate any edits; however, these files become the destination library's originals. This means that you can't revert to their earliest pre-import version.

Unmodified originals don't show any edits that you made when they were in the source library. This gives you flexibility for later editing, but recreating your edits might take substantial work.

How to export edited versions

1. In the Photos app, select the photos and videos that you want to export. To select multiple items, press and hold the Command key while you click. To select a group of items in order, click the first one, then press and hold the Shift key while you click the last one. This selects all of the items between the two that you clicked.
2. Choose File > Export > Export [number].
   
3. An export dialog appears.
   
   • In the Photos section, set Photo Kind to JPEG, TIFF, or PNG. JPEG recompresses your photos, which may result in smaller file sizes. TIFF and PNG files are higher fidelity and may result in larger file sizes.
   • In the Videos section, choose a Movie Quality setting. This section appears only if your selected items include videos.
   • In the Info section, select the checkboxes if you want to preserve metadata and location data in the exported files.
   • In the File Naming section, set File Name to Use File Name and set Subfolder Format to either Moment Name or None. Moment Name creates a subfolder for each Moment that's represented in your selected items. This is useful if you'd like to create an Album in the destination library for each Moment. The None option exports all of the files directly into the destination folder.
     
4. Click Export. A Finder dialog appears.
   
5. Navigate to the location where you want to save the files, such as the Desktop or an external drive. Click New Folder if you create a new folder for your exported items.
6. Click Export.

How to export unmodified originals

1. In the Photos app, then select the photos and videos that you want to export. To select multiple items, press and hold the Command key while you click. To select a group of items in order, click the first one, then press and hold the Shift key while you click the last one. This selects all of the items between the two that you clicked.
2. Choose File > Export > Export Unmodified Original.
   
3. An export dialog appears.
   
   • If your photos include IPTC metadata (such as titles or keywords) that you want to keep, select the Export IPTC as XMP checkbox.
   • Leave the File Name setting on Use File Name.
   • Next to Subfolder Format, choose Moment Name or None. Moment Name creates a subfolder for each Moment that's represented in your selected items. This is useful if you'd like to create an Album in the destination library for each Moment. The None option exports all of the files directly into the destination folder.
     
4. Click Export. A Finder dialog appears.
   
5. Navigate to the location where you want to save the files, such as the Desktop or an external drive. Click New Folder if you create a new folder for your exported items.
6. Click Export Originals.

How to import photos and videos into the destination library

Open the destination library, then drag the folder that contains your exported items into the main area that shows your other photos and videos. When a green plus sign appears on your pointer, you can release the folder.

The photos in the folder are sorted into Moments based on their creation dates and locations. The videos are sorted based on the date you exported them from the source library.

If you created subfolders when you exported the items and you want to create an Album for each subfolder, follow these steps:

1. In the Finder, open a subfolder.
2. Select all of the photos and videos within the subfolder.
3. Drag the items onto My Albums in the Photos sidebar.
4. Name the Album in the highlighted text box that appears in the sidebar.
   
5. Repeat for each subfolder.

Save space by deleting the source library

If you're sure that you've exported all of the photos and videos that you want to keep from the source library, you can delete it to save disk space on your Mac.

First, open the Finder and find the source library that you want to delete. By default, photo libraries are stored in your Pictures folder. If you can't find the library, follow the steps to choose a library; the path to the selected library's location appears in the Choose Library window.

Next, move the source library to the Trash. Then choose Finder > Empty Trash to permanently delete the files.

Sync Two Photo Libraries Macbook

Learn more

Photos in your System Photo Library are available in apps like iMovie, Pages and Keynote. You can also sync them to iOS devices and Apple TV via iTunes. And if you want to use your own images as your desktop picture or screen saver, the images need to be in your System Photo Library before you can select them in System Preferences.

If you have only one photo library, then it's the System Photo Library. Otherwise, the first photo library that you create or open in Photos will become the System Photo Library. If you have more than one library, you might need to designate a System Photo Library, so other apps can access the photos and videos you want them to use.

Follow these steps to designate a System Photo Library:

1. Quit Photos.
2. Hold down the Option key, then open Photos. One of the photo libraries is already designated as YourLibraryName (System Photo Library).
3. Choose the library you want to designate as the System Photo Library.
4. After Photos opens the library, choose Photos > Preferences from the menu bar.
5. Click the General tab.
6. Click the Use as System Photo Library button.

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If you open a second or different library in the Photos app, and you haven't designated it as the System Photo Library, other applications will use photos from the original System Photo Library. Hold down the Option key when you open Photos to see which library is set as the System Photo Library.

iCloud and the System Photo Library

You can use iCloud Photos, Shared Albums and My Photo Stream only with the System Photo Library. If you choose a different library in Photos without designating it as the System Photo Library, the iCloud tab in Photos preferences is disabled:

Two Photo Libraries On Mac

If you designate a new library as the System Photo Library and then turn on iCloud Photos, the photos and videos in the new library will merge with those already in your iCloud Photos. If you want to keep the contents of your photo libraries separate, don’t turn on iCloud Photos for more than one library in Photos.