I have tried to deactivate all plugins, and unfortunately it didn’t help. The issue did happen again this morning, and while I was spitting nails, and trying a few different things to fix the issue, I believe I stumbled upon a fix.
For me, if I upload multiple files to my media library, the issue unfolds. Time and time again. I noticed, that if I deleted the files, then went back into my media library and uploaded them one at a time, the images worked just fine when publishing or previewing.
It appears the problem is with the multi-file uploader. Grrrr!
I am crossing my fingers that my “find” is real, but I would like some other resolution here, other than uploading images one at a time. Seems like the system should be robust enough to handle multiple files.
I hope this helps someone out there with the same headache, until the file uploader can be fixed.