Hi there,

When a non-working theme is enabled, you could try seeing where the missing picture is trying to be loaded from. One way to do that is via right clicking the (not loaded) image and click "Open image in new tab" (or similar). The new tab will most likely give you a 404 (or similar) error, but check the URL where it is trying to load the image from. My guess is it's trying to load it from an incorrect domain (possibly a domain or IP address that is wrong, or perhaps even "localhost").

Another way of achieving a similar end is use the browser's built in "developer tools" when viewing your page. I'm a chrome user so it's either a or Menu >> "More Tools" >> "Developer Tools", but Firefox has a similar set of tools (and most likely other browsers too). The missing images (and likely some missing CSS and/or javascript too) should show up and you can check the incorrect URL there.

That will at least assist us to understand why the resources aren't loading. And perhaps even give us a hint of what might be wrong. It could even be as simple as the images are only served via http whereas the rest of the site is https.

Another idea that may also be worth trying is to check your Apache error log. That may give us some additional insight. You'll find your Apache log here: /var/log/apache2/error.log.