iTunes can't "see" Photos app folders...

I've scoured the web for this issue and can't find a solution that solves the problem. I just discovered that my iPhone wasn't reflecting changes to one of my Photos albums, then discovered that iTunes wasn't set to Sync photos at all, which was weird because there were lots of Photos albums already on the phone. This is especially weird because I know that I had previously set various folders to import from Photos when I upgraded to a larger capacity iPhone.

After turning the Sync option on, I then discovered that while "Pictures" was already selected as the "Copy photos from:" option, it would not show me any of the actual Photos albums/folders when I selected the "Selected folders" option. All that appears is other folders that happen to be inside of my Pictures folder (Lightroom, Photo Booth, etc.). Here's what I've tried so far:

- Rebooted

- Updated iTunes, then quit/open both that and Photos

- Checked the Info panel for my Photos collection (that is, 'Photos.photoslibrary'), including permissions (all users can both see and edit)

- Deleted the 'iPod Photo Cache' folders, one in Pictures and one inside of Photos

- Option-launched Photos to switch to a different source folder, then back again, then re-launched iTunes

- Chose another source of photos in iTunes, re-launched, then switched back to Pictures

- Allowed iTunes to delete all photos from my phone (that is, other than ones that the phone took)

No dice. This is what I continue to see...

Very annoying. Anybody have any ideas that I haven't tried?