Some linked images not loading on Chrome browser (theme-specific).

Hi,

I’m having issues using my blog http://www.immiandgreg.de for some months now and I finally had the time to get to it and ask here.

I’m using the Blogum theme from WPShower which is free and somehow it seems the support there ran out.
However, my issue is the following:
Images in my posts are linked via html to Flickr. When I visit the page in Chrome it will load the images of the posts that are visible (without scrolling). So on 100% one post/img will show, on 25% four posts/images will show.
The images of the other posts are not loading. This also happens in the single post view.

This happens on every Chrome browser (various platforms, mobile, …) but not on Opera/Firefox/etc. I already cleared the cache and so on, disabled all plugins and tried a different theme. All good in the Twenty… themes.

This might be easy to fix but my very restricted knowledge of css is at the moment fully exhausted. I already created a local copy to fiddle around with it.

Any help much appreciated.

Cheers