Can't upload photos to FB anymore

I used to be able to click on "Photos" when in FB and open up my photo library and click on a photo to open, now it doesn't show anything, the rainbow wheel just spins around. And it won't let me click on "Use as System Photo Library" anymore?

It has been over 10 minutes and the gear icon is still spinning. No photos are available like they used to be before the system upgrade.

When I go to preferences under Photos - it won't let me highlight "Use As System Photo Library" should it? It just says "show in favorites"

I upgraded to High Sierra two days ago. I have 4200 photos. If I open the Photos App, they are all there. It is only when I go to post to FB (that I have noticed so far). So, should I just let it run? I know I had to do that initially when we first got our mac.

I will try this and let you know if it worked.

This is the window I have and it won't populate with my photos like it did before. Do I have to wait a really long time for the photos to upload? I have cancelled out of it several times.

Not sure what it is showing solved, but this problem is NOT SOLVED! Please see screen shot and advise accordingly.

Will do. I will try it tomorrow as Sunday is a tech free day. I can start the process in the am and let it run. I appreciate your help.

It has been several hours and the gear is still spinning and no photos have been uploaded. Is this normal? Or do I need to do something else?

And, everything seems to be frozen - I can't click on other tabs that are showing across the top while this gear is spinning....