When I look at the page’s error logs it seems the issue is not Connections related, at least on the surface.
Load the page in Chrome, hit the F12 key and then click the Console tab. You’ll see 404 and 500 errors for many other images too. Connections does handle this gracefully by not loading trying to load the image at all.
The issue could simply be that the memory allocated to PHP has been exhausted. My first suggestion is to try to increase it to see if the issues resolves. Here’s a link to an excellent blog post that outlines several methods to try to increase the amount. Since different methods will work on different hosts, I suggest starting at the top of the list and working your way down until hopefully the issue is resolved.
If that does not fix it, then I’ll need a temp admin account and FTP access so I can take a closer look. You can post the details here as a private reply. Please follow-up with a non-private reply otherwise I will not know you posted the login details.
I hope this helps. Let me know how it goes.