Thumbnails not found on Product Pages

[quetschwurst]

Please have a look on this example:
http://tp-group.info/produkte/motor00/motoren00/motoren/cummins-b-5-9-detail
The Thumbs are not shown, but if you click on them, the correct large pictures are displayed.
This problem exists since the last VM Update (current is v 2.0.22a on joomla 2.5.11)

I have no idea why the thumbs are not shown...

[K&K media production]

i see the thumbs

[quetschwurst]

i see the thumbs

I do also see them now... The problem was solved, there was something wrong in mediahandler.php