My images have fallen and they can't get up!

I have a very strange issue. I can add a blog post to my site and it looks great. When I add an image to a blog post, all the posts on the page disappear and I am left with just the header image.

The site is hosted by Hostway.com and I have installed the latest version of WordPress & all plug-ins have been updated. I have even uploaded a fresh version of the wp-includes and wp-admin folders.

I tried deactivating all plug-ins and reactivated them one by one. I also tried one of the default themes and had the same issue.

Now I’m just stumped.
Would love some other options to try, please! Thank you!