Mhm, I found this:
I also have the plugin “RPS Image Gallery”, so that clicking on the images mean you go to the url-attachment, instead of opening the image itself.
When I deactive this plugin, I can see the pagination works on the page.
But in that case I have two other problems:
* there are some images missing/not shown in the gallery. Any idea?
* clicking on the image means again that the image will be opened instead of the url.
Any suggestions maybe?