The Photos app for Mac, iPhone & iOS is the best place to keep digital pictures and videos. With the optional iCloud Photo Library feature, all photos & videos are kept safe on Apple’s servers. Every picture stored on the Mac, iPhone or iPad is compared to the ones already in iCloud Photo Library. Any new images are copied to the cloud, and the photos already in the cloud are added to the Mac or device. Even if you don’t need these features in the long term, the capability to merge photos from several computers & devices is useful.
To combine photos from different devices & Macs, see instructions for enabling iCloud Photo Library on iPhone, iPad & Mac.
An iPhone or iPad can only have one Apple Photos library. Macs can have more than one library. For example, you might have a Photos library on your internal drive and another on an external volume. Or perhaps several users on a single Mac have their own Photos libraries. Ordinarily, only one Photos library can sync with iCloud Photo Library – this is called the System library. We’ll show you how to work around this limitation to combine several libraries.
Carefully review the steps outlined below to determine if this is within your skill set. Don’t be afraid to ask for expert help!
Combining Photos libraries
- Connect to the fastest internet available and plug laptops into the A/C outlet. Uploading & downloading takes a lot of power.
- Determine which of your Photos library will be your primary library. Usually, this is the largest Photos library, or your current System library. But don’t do anything with it yet – we’ll address the primary library last.
- Copy each additional Photos library to an external drive. See instructions.
- Create an empty Mac user account. Call it Photosync. This is the key to making a Mac sync several Photos libraries.
- Sign into the Photosync account, then log into iCloud. You’ll need to use the same iCloud account with each Mac account to sync photos.
- Click the Photos icon and immediately hold the Option key. You’re given the ability to select a Photos library, which will be the one to merge with iCloud. Start with the smallest Photos library. (We’ll address the primary or largest library last.)
- Open the Photos preferences. Click the iCloud icon and check the box to turn on iCloud Photo Library. Set it as the System library. You might need to purchase additional iCloud storage before continuing.
- Choose Optimize Mac Storage. This downloads low-res photos & videos from iCloud, while uploading full-res images from this library as quickly as possible.
- If possible, wait until iCloud completes uploading & downloading. This process takes time – from hours to days, depending on the size of the library and internet speed. Images are uploaded to the cloud in the background as long as the computer is turned on and signed into the Photosync user account. Monitor upload/download progress in the Photos preferences window. For large libraries, you can sign into the Photosync account and let it run at night, then sign out and use your normal user account when you need to work on other projects. Uploading will continue the next time you sign back into Photosync. When sync is complete, quit Photos.
- Repeat steps 6–9 for each Photos library you want to sync. Work your way up to the largest library.
- The last library is your primary Photos library – usually in the original Mac user account. When you turn on iCloud Photo Library, you may need to set the Photos preferences to Optimize Mac Storage if the combined high-res originals won’t all fit on the drive.
- Remove the Photosync user accounts and old Photos libraries when you’re sure everything is in the primary library.
Copying a Photos library from an external drive to the cloud
Sometimes a Photos library has outgrown your internal storage. Perhaps you’ve been storing it on an external drive. If you’d like to access the photo library without having to attach the drive, move the library to iCloud and then use iCloud Photo Library to create a new smaller library on the internal drive without overfilling it.
- Connect to the fastest internet available and plug laptops into the A/C outlet. Uploading & downloading takes a lot of power.
- Click the Photos icon and immediately hold the Option key. Select the Photos library on the external drive.
- Open the Photos preferences. Click the iCloud icon and check the box to turn on iCloud Photo Library. Set it as the System library. You might need to purchase additional iCloud storage.
- If possible, wait until iCloud completes uploading & downloading. This process takes time – from hours to days, depending on the size of the library and internet speed. Images are uploaded to the cloud in the background as long as the computer is turned on. Monitor upload/download progress in the Photos preferences window. When sync is complete, quit Photos. You may now disconnect the external drive.
- Click the Photos icon and immediately hold the Option key. Choose Create New… and save the Photos library in the default home/Pictures folder on the main drive.
- Open the Photos preferences. Click the iCloud icon and set this library as the System library.
- Choose Optimize Mac Storage. iCloud downloads all your photos & videos. The Mac will manage storage automatically by intelligently downloading high-res images on-demand without filling the drive.
- You may remove old Photos library on the external drive if you need space.
About the Faces album
When photos are downloaded from iCloud Photo Library, they retain albums & organization, original images & subsequent edits (adjustments, filters & crop), as well as most metadata (locations, etc). Unfortunately, people tags do not transfer between libraries. If you had used the Photos facial-recognition technology and identified the names of people in your images, you’ll have to repeat this process after transferring/merging photos.
Learn more about graphics & media.
