baluo on "Newbie -- Images not shown"

Hi, I have uploaded images and edited their display (label, date) and settings and now face the problem that

* not all of the thumbnails are shown
* regardless of thumbnails shown or not, large numbers of the standard size images are not shown
* while the original size images *are* shown.

<http://grweb.org/photogallery/201210-kangaroo-island-south-australia/>
This is true for all three test albums.

What could be the cause of this error?

Thanks, Gerhard