Chrome doesn't like mixed sources. Since DU is delivered securely over https:// your images would also need to be delivered using https:// but some of yours are not so Chrome will block them and tag them ad "Not Secure".

...I see that although the correct image will show if I right click on "open in a new window" the image comes up correctly, but is labeled as not secure.

As it was working before, there must be a new security patch in Chrome. I'll ask my son if he can address it.