well, yes, I changed the theme and all my thumbnails are gone and replaced with that "zp" graphic.
What happened?
Can I "recreate" thumbnails?

http://www.zenphoto.org/support/topic.php?id=3760

yes, ... I had a look at these.

...but I found something strage in the "theme-settings" where you can set the "standard thumbnail size" - I had 180 there and after this "problem" there was this: <script type=
Where did that come from?!

well, I changed it back to 180
and also changed the size of the thumbnails....

it was ok for a moment...

... and now there is
<script type=
15" />

"images per page"

Something is very strange here....

I will try to overwright all zp-core stuff

... ok, works fine again - after reinstalling.