You may choose to store all your photos - whether taken on your iPhone, compact, or SLR camera - on your Mac. This is a great way of making sure they are backed up, however, if you are a bit 'snap happy', then your Mac storage space can quickly run out. 

One option is to use iCloud Photo Library to store full-res versions in the cloud, and lower-res versions on your computer (as well as being able to view them on other devices). But iCloud Photo Library isn't a backup as such - if you delete a photo that was taken on your iPhone it will be deleted from the cloud too.

So what can you do if you want to keep all of your photos somewhere safe and you don't have room on your Mac to do so?

Luckily, it’s easy to move the Photos library on your Mac onto an external drive. Then, whenever you open the Photos app on your Mac, it will access this drive and show you your photos (as long as it's plugged in, of course!)

If you want to back up the photos on your iPhone we have a separate article here.

Want to move your photos from your Mac to an external storage device, either as a backup or to free up space on your Mac? It’s easy, read on…

The process here will be a bit different depending on whether you already have all your photos stored on your Mac, or if you have all your photos stored in iCloud Photo Library, but want to back them up to an external device. We address both scenarios below.

If you are a bit short of space on your Mac, here’s how to transfer your photo library to an external drive and store it there.

How to copy the Photos library to a hard drive

If you have a large photo library on your Mac, transferring the photos to an external drive can save you valuable storage space.

We advise you to get a reasonably fast external storage device. If you have a large library a hard drive with a few TB of storage may appeal, but if you intend to spend time using the Photos app editing the photos and so on, you may want to consider flash storage (an SSD). Either way, we would recommend a Thunderbolt or USB-3/USB Type-C interface for the fastest transfers. You can check out our guide to the best hard drives here and our best SSDs here.

Before you start, you need to make sure the external drive you are using is formatted for Mac OS Extended (Journaled). Open Disk Utility and check what format is being used. If you need to reformat the disk, follow the steps in this tutorial: How to format a disk for Mac. If the disk needs to be reformatted, you will need to Erase the disk, so make sure you copy anything from the disk first, then click on Erase and choose Mac OS Extended (Journaled).

  1. If you have Photos open, quit it.
  2. Locate the Photos library on your Mac - you will find it in your Pictures folder. Open a Finder window and click on your Mac Home folder (the icon looks like a house and it will probably be identified by your username). Click on Pictures.
  3. Inside this folder you will see the Photos Library, identifier by an icon like the one below.
  4. (If you wanted to view the contents of this library without using Photo, you could right-click/control-click on it and choose Show Package Contents from the options. This will show you the master folders containing your photos. (You may want to do this if you were copying images to a PC since the PC may not be able to view the contents of the Photos Library).
  5. If you right click on the Photos Library package you can choose Get Info to see just how large the library is - you will want to ensure that the drive you are planning to copy it too is large enough to accommodate it, and any additional photos you add at a later date.
  6. Copy the Photos Library to the external drive. You can drag and drop.
  7. Wait while it copies over - this may take a while depending on the size of your library and the speed of the connection to the drive.
  8. Once the library has copied over, hold down the Option/Alt key and launch Photos.
  9. Click Other Library and navigate to the new location on the external drive.
  10. If you see a message that there are items that need to be downloaded from iCloud Photo Library you should click on Delete Incomplete Items - you will be able to download them from iCloud later.
  11. Now that Photos is open, click on Preferences > General and choose Use as System Photo Library (you have to do this in order to get it to work with iCloud Photo Library if you use it).
  12. Now go to System Preferences > iCloud > Photos > Options, and Select iCloud Photo Library to turn that back on.
  13. Make sure all the photos are there, and that everything is working before deleting the Photo library on your Mac. Remember you will need to plug in your drive (or connect to it via WiFi in order to see your photos there).

How to back up your iCloud Photo Library

If you have iCloud Photo Library and want to back up all your photos to a storage device attached to your Mac you can follow the guide above, but you will need to add the step of downloading the images from iCloud.

Assuming you have already copied your Photos library onto the external storage device, you can follow these steps.

  1. Open Photos on your Mac.
  2. Click Photos > Preferences.
  3. Click on the iCloud tab.
  4. Choose Download originals to this Mac.

Now all your iCloud photos will be saved on the storage device. (Alternatively, if you do this step first prior to moving your photo library to the external drive, the images will be added to your Mac - but if you are short of storage space you probably wouldn't want to do that.)