Photos don't display

Hello,
I have a recent problem with some photos on my site. They don’t display. Only the descprition appears. I don’t understand why and can’t see a way to resolve this problem. I don’t know if it has to do with a configuration of my theme or a loading issue, maybe ? I have been using Jetpack to accelarate the loading time for a long time and it used to work correctly : this is what is called “accélérateur de site” in the French version I am using. I have not changed anything in the configuration of jetpack recently, though.
I had tried to activate the second item called in French “activer le chargement optimisé des images” in Jetpack a few weeks ago but it never worked correctly. I had to refresh a few times each page so that all my images load and appear. So I decided to stop using this mode. Now I see that this same problem appears even though I have not reactivated this mode.
We can see the problem on this article for instance :
https://linactuelle.fr/index.php/2018/12/08/serge-latouche-le-culte-de-la-croissance/
as well as on this page search :
https://linactuelle.fr/?s=Illich

Sorry, I am not a fluent English person (I am French) and a recent user of the theme and of wordpress.
Thanks in advance for your tips and advice.
Stéphanie.

I have same inssue in my site https://laguajirahoy.com

inssue solved, I tried disabling all plugins except for the theme.

I have almost the same issue. On the media library the images are not showing, just a gray image. Most of the images are like that. And If I try to upload a new one I get a “http error” and the image becomes a gray icon.

I tried deactivating all plugins but this didn’t solve the issue. Then I tried activating another theme and the problem was solved. So the issue is on the Newspaper theme.

Any tips on the solution for this case please?

I solved this by upgrading my site to PHP 7.0

I’m now having a similar issue and not sure how to fix it. When I upload my photos, they give me an http error, but after I close out and refresh they appear; however, they only appear grayed out as shown in this screenshot:
Upload Photos
Once I log back in and get the grayed photos to show up, I can select one, but it doesn’t actually populate on the actual website page. I can see the thumbnail preview in the left hand menu, but it will not show up in the actual Exhibit:
Photo Thumbnail