Cannot drag photos from Photos to iMovie timeline

FWIW, Apple found the problem.

I had unintentionally turned off iMovie access to Photos at:

Apple > System Settings > Privacy & Security > Photos > iMovie.

I have no idea how that happened!

Dick

Here's some more info.

1. I can drag media to the desktop and drag it to the timeline. That's an extra step I'd like to avoid.
2. When I select Photos in the iMovie Browser, nothing appears.
3. None of the four possible selections I select in the drop-down at the top of the browser yields anything.
4. I've deleted iMovie's Settings (Start with Option & Command Keys down, Select Delete in resulting dialog box, then restarted) to no avail. (Is this the proper way to delete Settings with a Silicon Mac? It's how another poster suggests resolving this issue.)
5. I've restarted several times and even powered down/up (rebooted).

A screen shot of my iMovie window is attached. The clips in the timeline were dragged from other sources.

Please help.

Dick