Do you mean you are using "Mac OS Extended (Journaled)?" Or are you using Mac OS Extended (Journaled, Encrypted)?" Every version of "Extended" has "(Journaled)" in the name. You can check the format of a drive with the command-i information window:

This drive is formatted APFS
For information on using an external drive, check here:
Move your Photos library to save space on your Mac - Apple Support
Make sure that Time Machine hasn't been on the hard drive since it was formatted. And check the "Ignore ownership" tag at the bottom.

How are you importing pictures to Photos? Do you use File>Import, drag and drop, Image Capture, Air Drop, or what? Do you use iCloud for syncing Photos on your devices?
Let us know any extra information...