Some images don’t display

Thanks for an excellent plug-in, which I’ve been using for several years.

I’ve had an ongoing problem with some images not displaying. Instead, they sometimes appear as links.

In the example link I’ve provided, only two images are displaying for me (lower down the page). If you click on the English flag to go to the English version of the page, even those two images don’t display, even though they’re the same image source. All the images on both pages should display. Any idea how I can fix this?

The page I need help with: [log in to see the link]