I found the problem. Although the images were marked as .JPEG, they were actually .WEBP images.
Those are .JPEG'S and .PGN'S that are converted by a site to save space.
Sorry, It took me a while to convert all of the images back to .JPEG's,
They were mixed. Most were originally JPEG's, but some were PGN's.
Here they all are, 97 images, converted to JPEG's in a Zip file.