Hello webthings
I had the exact same problem yesterday after updating the plugin, any new post would do this, but all my old posts worked fine.
i took a look at the code for showing the gallerys, and found this:
<img class=”ngg_displayed_gallery mceItem” src=”http://www.smedeklubbenphonix.dk/WordPress/nextgen-attach_to_post/preview/id–1318″ alt=”” />
where the old post where like this:
<img class=”ngg_displayed_gallery mceItem” src=”http://www.smedeklubbenphonix.dk/nextgen-attach_to_post/preview/id–1318″ alt=”” />
So after removing the /wordpress, from the new link, everything worked like it used to.
hope this will help you.