Only fetch images for news items with images

This can now be attempted on the frontend since the backend changes have been merged in:
- https://github.com/fsek/WebWebWeb/pull/532

I expect this will be done easily by disabling the custom image container used for each news item, if that news item doesn't have an image.

Review the merged backend changes in pull request #532, then locate the frontend custom image container used for each news item. Check how image presence is exposed to the frontend and verify that news items without images no longer trigger image fetching or display the custom container.

Written by the indexing model from the issue text.