By Jason Snell
February 1, 2016 12:49 PM PT
Copy files back into a Photos for Mac library
Note: This story has not been updated for several years.

Longtime Mac writer Ted Landau posted this on Twitter earlier today, and since I wrote the book on Photos for Mac, I was able to help him out:
Help! I was unaware “Copy Items to Photos Library” was disabled in Photos. Is there a quick way to now truly import all referenced photos?
— Ted Landau (@tedlandau) February 1, 2016
By default, every image you import into Photos from your hard drive is copied into the Photos library. You can throw away the file that’s out on your desktop if you like, because a copy of it now resides inside the Photos library package. But some people want more control over their photos, preferring to organize their image files themselves, in the Finder. For those people, Apple offers a setting in Photos Preferences: “Copy items to the Photos library.” If you uncheck that box, any image you copy into Photos will not be copied into the library package. If you delete the photo later, Photos won’t be able to do anything to bring it back.
Accidentally unchecking that box can lead to some terrible consequences—like you deleting your photos without realizing you have no backup! Fortunately, in Ted’s case the photos still existed—but he had moved them to an external volume. Ted’s question then, was twofold: Can he do something so that those images are entirely copied into his Photos library, and what happens if he’s moved the image files in the meantime?

First off, it’s worth noting that Photos displays a special icon on any photo that hasn’t been copied into its library: In the bottom-left corner of a thumbnail, it will display an image of a square with an arrow. (If it can’t find the source image, this becomes a yellow alert symbol with an arrow.) You can toggle this icon on and off via the View: Metadata: Referenced File command.)
Fortunately for Ted, Photos does include a command that will find all the source image files and copy them into the library. To perform this task, open Photos and select the photos you’d like the app to copy, then choose File: Consolidate. If you haven’t moved the files anywhere, once this task is completed your Photos library will be whole again.

Ted moved his items to a different hard drive, but if Photos can’t find a certain photo in its original location, it will ask you to pick a folder to search in. Ted was able to point Photos at his alternate disk, and then the app was able to import all of those files.
So if you ever regret leaving items outside of your Photos library, you can import them later with the Consolidate command. But for most people, it’s a better idea to leave the “Copy items to the Photos library” preference checked, now and forever.
[If you want more tips about Photos, check out my book, Photos for Mac: A Take Control Crash Course.]
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