How do I copy all photos from Photos App to an external drive? After searching here, I'm still confused about how the Photos App library works. I'd like to copy (or simply move) all of my photos (10k+) from the Photos app to an external drive, so that I can then use Lightroom to manage them. I need to do this to free up space (approx. 26gb) on my hard drive.

I've found the Photos App library and have copied it over to an external drive, but now I'm wondering how I "open" this file so that I can then import these photos into Lightroom. Is there a way to view all the original, individual photos in a simple folder that I can then work more easily with? 

FWIW, I do have iCloud and my photos are automatically backed up there. There are approximately 10K photos in the Photos library. Any advice on how to best proceed?
Is your Lightroom installation also on your Mac OS partition?

If you want to edit the files in Lightroom without having to "extract" them into a separate folder, you should:


Open the folder containing the Photos library in Finder.
Right-click the Photos Library and click "show package contents".
Open the Masters folder and right-click on a year folder and select "make alias".  (This is necessary, since the "make alias" option doesn't exist when you right-click on the Masters folder for no apparent reason.)
Command+I on the new alias and click "choose destination", then drag the Masters folder into the dialogue that opens.
Rename your alias and drag it wherever is best for you.