SOME images have no thumbnail and no image on page

This has been happening for a while – I upload a few images and some of them don’t show a thumbnail in the media gallery and if I insert them into a page they don’t show, either under visual or in the view page.

Please note that it’s only SOME images that do this, today I upload 6 jpgs and 3 of them turned out blank.

I have media set to upload into wp-content/uploads

The image has loaded because I can see it in the folder. (With both CPanel or FTP – it’s there with the usual different sizes).

If I try to ‘view image’ with CPanel, that image won’t display.

When an image does this, I try to upload it again, both via the add media button while editing the page and by adding it to the Media Library.

If the image won’t load on one website, then it refuses to load on several other websites, on different servers.

I have compared the image properties/details against images that have loaded and everything is identical.

I have opened the image in Photoshop CS6 and saved it with a new name- didn’t work

I have used smushit to remove all information on it – didn’t work.

It can’t be the php version because some of the websites I’ve tested this on have hundreds of images with no problems.

It can’t be the website, wordpress 9.2 or the plugins, because the image refuses to work on other websites with different plugins, different versions of wordpress, on different servers. PLUS the image is a standard jpg not something unusual.

All the images are created with Photoshop CS6 on a mac and supplied to me.

HERE’S THE WEIRDEST THING THAT THROWS OUT ANY THEORY I CAN THINK OF –
Today I took a screenshot of the image, using Greenshot, named it TEST1 – didn’t work!!– no thumbnail in the Media Library and no image on page.

At first I thought that the supplier must be doing something strange to some of the images, but today, when the SCREENSHOT failed as well, I ran out of ideas.

It’s as if the actual image contains something visual that WordPress doesn’t like, because with a screenshot nothing but the image is copied.

Naturally I’ve spent a long time searching, but everyone else has had trouble with all the images not working, not as in my case, only some of them.

Help!

Rob