The website in question is http://www.pumpaid.org.
Take this page:
This image is supposed to show in the main band below the navigation:
I can see the image is called when I view the page source. The image serves fine on its own. It just doesn't serve in the page itself.
And ditto for every image on the site excepting those in widgets.
I wondered if the WordPress database had 'lost' the images, so used the plugin Add To Server to make sure WordPress had all images registered in its media library. No effect.
I updated the .htaccess recently with Bulletproof Security so perhaps that caused the problem at the time without my noticing?
Any and all ideas gratefully received.