sharing external-drive photos from Library on Facebook
I just moved my Photo Library to an external drive (Passport, formatted MacOS Extended (Journaled)) to save space on the iMac hard drive. That worked great, except that when trying to add photos to a Facebook post, I get a message in the Add Photo screen of Facebook (in Firefox) that says "No Library Found, you can create a new one in Photos." But as far as I can tell, there really is a Photo Library that exists. This happens in both Safari and Firefox 133.0.3, Sonoma 14.6.1
What do I need to do to get to where adding photos to Facebook posts is doable, without my current workaround of copying and pasting each photo, one at a time? I really hope it's not moving the Photo Library back to the iMac hard drive. It's 180GB of photos, and the hard drive is almost full.
iMac 24″, macOS 14.6