Media Library and most, but not all images problems

Hi there, and thanks in advance.

The images on my site are not working– but it is more complex than that.

I have tried everything here: https://www.ads-software.com/support/topic/read-this-first-%E2%80%93-wordpress-42-master-list?replies=4

But still, the images that worked before the new WP upgrade don’t work, except for just a handful of them.

They don’t show up in the media library (except for three or four images) and they don’t show up on the website.

I get the broken image symbol in Media Library, and even though the permissions are correct, I cannot access the images directly at their link.

Anybody else have this problem? Have you resolved it successfully?