How to Combine Multiple Photos Libraries Into a Single Library

If you’ve been working with the Mac’s Photos app (or even the older iPhoto or Aperture apps) for any length of time, there’s a good chance you have multiple image libraries to help you organize your pictures.

In the past, I’ve used Aperture to store my business-related images, and iPhoto to keep my personal pictures organized. When Photos came along, I set it up to work with either library.

If you’ve done this, too, then you know you must hold down the option key when you launch Photos to choose which Photos Library you want to use, unless you’re lucky enough to have the target library open right off the bat (and that never happens).

(Holding down the option key while launching Photos allows you to pick which library to use.)

Performing a switcheroo every time gets old pretty quickly, so I decided the best thing to do would be to merge the two libraries into one.

Merge Using iCloud Photo Library
In this article, we’re going to look at the various methods available in the hope that at least one of them will meet your needs when it comes to merging image libraries, or even just moving a few images around from one library to another. We’ll start with the iCloud Photo Library.


  • Able to merge image libraries while retaining all metadata, such as recognized faces, events, albums, and projects.
  • Retains both the master image and any current edits, allowing you to undo edits, or continue to perform new edits without altering the master.


  • Requires enough iCloud storage space to hold both the main library as well as the one you intend to merge.
  • All photos in both libraries must be uploaded to iCloud.
  • The iCloud photo library may sync to any device you have that uses the same iCloud account. This could cause overage in cellular data plans if an iPad or iPhone is being synced.
  • Extremely slow. The upload and download from iCloud Photo Library isn’t particularly fast. A large photo library could take a week or more for the process to complete.

(The main library, which will hold all the merged photos, must be designated as the System Photo Library.)

To start the process, you must decide which Photo library you wish to be your main library. This is the library that will eventually contain all the merged photos. In the instructions that follow, when you see the term main library, it’s this library that is the focus of the instructions.

1) Launch Photos while holding down the option key.
2) The Choose Library dialog box will appear. Select the library you wish to use as your main library from the list, and then click the Choose Library button.
3) In the Photos app, select Preferences from the Photos menu.
4) Select the General tab.
5) The main library needs to be the System Photo Library. If needed, click the Use as System Photo Library button. If it’s already the System Photo Library, the button will be dimmed.
6) Select the iCloud tab.
7) Place a checkmark in the iCloud Photo Library box.
8) Make sure the option to Download Originals to this Mac is selected.
9) Photos will start the upload process to iCloud. An estimate of the number of images and the amount of space they will need will be displayed.
10) Once the process is complete, you can quit the Photos app.

Merging Additional Image Libraries:

1) To merge additional libraries, launch Photos while holding down the option key, and then select the next library you wish to merge with the main library.
2) Follow steps 3 through 10, above.
3) Repeat for each image library you wish to merge with the main Photos library.

Accessing the iCloud Photo Library With All the Merged Images:

At this point, the iCloud Photo Library contains all of the images from the libraries you’ve merged together. The last step is to open Photos with the main library and sync all of the iCloud images back to your Mac.

1) Launch Photos while holding down the option key.
2) Select the main library from the list of available image libraries.
3) In Preferences, select the General tab. Make sure the library is the System Photo Library.
4) In Preferences, select the iCloud tab. Place a checkmark in the iCloud Photo Library box.
5) Make sure Download Originals to this Mac is selected.
6) iCloud will begin downloading all of the originals you had previously uploaded to iCloud’s Photo Library.
7) Once again, this process can take quite a while, but when it’s completed, you’ll have merged all of your image libraries into a single Photos library.

At this point you can either leave iCloud Photo Library enabled in the Photos preferences, or turn the function off, depending on whether you wish to keep your Photos Library synced with other Macs, iPads, and iPhones.

(Uploading image libraries to the iCloud Photo Library can take a long time, even weeks, depending on the size of the libraries.)

Merge Using Export/Import
Another way to merge Photos Libraries is with the Export/Import functions.


  • Relatively fast.
  • Can export and import both the masters and any edits.


Export Images:

1) Launch Photos while holding down the option key.
2) Select the photo library you wish to export images from, and then click the Choose Library button.
3) In the Photos app, select the images you wish to export. If you wish to export all, you can choose Select All from the Edit menu.
4) Select Export, Unmodified Originals for the amount of photos.
5) In the dialog box that opens, use the dropdown menus to select the file name format to use, as well as the subfolder naming (if needed) to use. You should also put a checkmark next to the Export IPTC as XMP option.
6) Click the Export button.
7) In the dialog box that opens, select a location on your Mac to export the files to. I highly recommend creating a folder to export them to, such as Photos Export.
8) When the export process is finished, quit Photos.

(The export options include designating the file names to use, and any subfolder format.)

Import Images:

1) Launch Photos while holding down the option key.
2) Select the Photos library that you want to import the images into.
3) Click the Choose Library button.
4) In the Photos app, select Import from the File menu.
5) In the dialog box that opens, browse to the folder that contains the images you exported previously.
6) Select the folder, and then click the Review for Import button.
7) The images will be displayed in the Photos app. You can select specific images to import, or you can import all of the images. Click the appropriate import button.
8) The images will be imported into the currently open Photos library.
9) Repeat the export/import process for each image library you wish to merge.

Merge Using Terminal
The Terminal app offers a surprisingly simple method of merging Photos libraries.


  • Allows you to view the content of two or more Photos libraries at the same time.
  • You can drag and drop images between the open libraries.


  • Doesn’t retain image metadata.

This simple method of merging images makes use of the Mac’s ability to open multiple copies of the Photos app. This is accomplished by opening the first instance of Photos using the normal method, and any subsequent instances of Photos using Terminal.

1) Launch Photos while holding down the option key.
2) Select the image library you wish to copy images to, and then click the Choose Library button.
3) Launch Terminal, located at /Applications/Utilities.
4) At the Terminal prompt enter the following: open -n -a Photos
5) Once you’ve entered the line in Terminal, hold down the option key, and then press return or enter on the keyboard.
6) From the window that opens, select the Photos image library you wish to copy one or more images from, and then click the Choose Library button.
7) A second instance of Photos will open. Warning: Sometimes the second copy of Photos will open directly on top of the first, obscuring the fact that two instances of Photos are open.
8) Arrange the two Photos windows so that both can be seen.
9) Drag the images from the second instance of Photos to the first.
10) Repeat the process as needed.

Warning: Opening more than a few copies of Photos can severely deplete available memory and slow your Mac down. It’s best to have just two copies open at any one time.

Use the Finder to Merge Photos Libraries
Last but not least, you can use the Finder to merge Photos libraries.


  • Ensures the master images are copied.
  • Easier than opening multiple libraries within the Photos app.
  • Can help reduce the number of duplicate images added to your library.


  • Will likely lose most metadata, such as organization information, including Albums, Events, and Projects.

This method uses the Finder to locate the library folder that contains an alternative image library you wish to merge with your Photos main library. Photos libraries are usually located in the Pictures folder of your Home folder. The pathname should be ~/Pictures/Photos Libraries. The various image libraries you’ve created will be within the Photos Libraries folder. You should see items such as Photos Library and iCloud Photo Library, plus any additional libraries you’ve created.

The Finder merge method will work with other image libraries, such as those from iPhoto, located at ~/Pictures/iPhoto Libraries, and Aperture, located at ~/Pictures/Aperture Libraries. The instructions below assume you’re merging an alternate Photos library, but you can also merge iPhoto and Aperture libraries, just substitute the appropriate library locations.

1) Launch Photos, located in your /Applications folder.
2) Open a Finder window and browse to the Photos Library folder located at ~/Pictures/Photos Libraries.
3) Within the Photos Libraries folder, right-click (or control-click) the image library you wish to merge, then select Show Package Content from the dropdown menu.
4) In the new window you’ll find a folder named Masters.
5) Drag the Masters folder to the open Photos app and drop it onto the Photos window.
6) Photos will start importing the images. This can take quite a while, so be patient. If during the import Photos detects duplicate images, you’ll be given a “Don’t Import” option. If you don’t wish to keep answering the duplicate content messages, place a check mark in the “apply to all duplicates” box.

Once the import process is complete, you should check that the images are indeed within the main library. Once satisfied, you can delete the old library using the Finder.

(PowerPhotos from Fat Cat Software can simplify the process of merging libraries, handling many of the details for you.)

Third-Party Apps for Library Management
There are a number of third-party utility apps designed specifically to assist Mac users with merging and managing image libraries in Photos. One of the most popular is PowerPhotos.

PowerPhotos allows you to merge photo libraries without losing important metadata, such as Albums, Moments, and Events. In addition, PowerPhotos offers a number of ways to handle duplicates, including duplicate detection and how to choose between duplicates.

One of the main reasons I like PowerPhotos is that it can merge libraries while retaining most of the metadata that’s important to me. I don’t have to use up all my iCloud storage to do so, nor do I have to use additional storage space. And it goes without saying that PowerPhotos is much faster than syncing via iCloud.


  • Quick question about step 5 in the upload process of the icloud library method.

    I am merging three libraries. Do I leave the main library as the system library for each upload? Or do I have to change it each time?

    Based on reading the instructions I think I set the main library as the system library when I upload that library first and leave that first main as the system library when uploading libraries 2 and 3, but I want to confirm.

    • I did have the same question. There is only one main library that is the System Photo Library by default. Therefore step 5 seems unnecesarly.
      I would start with the none-main libraries and end with the main. Further I wonder why “Download Originals to this Mac” in none-main libraries as at that point it’s only necesarly to upload. Only in the last library, the main one, download should be selected and than only when you want that.
      When you have big libraries, as I have, make a new smal library and have a try. Don’t forget to make a backup, you’l never know.

  • Great article! Apple migrates to new libraries over time, screwing things up occassionnaly during migration. I have now several Photos libraries where all the events are gone and basically every date is an event. Horrible.

    Then the merge with the super-huge Aperture library occurred and now I have to re-think photo libraries.

    But I also moved my DSLR photos to Lightroom, which has a much simpler to grasp archiving function, albeit without the ‘sexiness’ of Photos.

    Basically I want Photos only for the sharing-with-friends and TV part, as Apple’s philosophy to throw your information out when moving to a new shiny app bothers me from an archiving perspective.
    They just don’t think or care about iPhoto archives from 2001.

    just my $0.02

  • The problem I see often is that people have both a newer Photos library and an older iPhoto library, which started out as duplicates of one another, but then the owner has been adding photos to either indiscriminately. Is there a third-party package that can work with the old format iPhoto library and move its contents (sans duplicates) to a new Photos library?

  • The really good way is to buy and use Power Photos. It does the job really well and saves a lot of time. I’m amazed that you haven’t included it. It is the follow up to iPhoto Library Manager and the developer is incredibly responsive and helpful.

    • Perhaps you didn’t read the entire article. Under the Third-Party Apps for Library Management section at the bottom of the article, Tom not only mentions PowerPhotos, but explains why he likes it.

      • Duh! I am having trouble believing I missed that. I guess my only response is that he wasted a lot of space describing rather complex and in some cases methods that leave things out when Power Photos does such a great job and is pretty inexpensive. I am a consultant and have cleaned up and merged a lot of iPhoto and Photos libraries for clients and I wouldn’t waste my time or their money on methods that give unsatisfactory results.

  • If you still prefer to use iPhoto (as I do), then iPhoto Library Manager will do the trick for you!