I hate to add to the backlog but i’m having the same problems since upgrading. To reiterate, my thumb-nails are no longer showing (only a button) I have deactivated and reactivated the plugin, cleared browser cache (no cache plugin used) and believe I have refreshed the permalinks (although not 100% on how to do this!).
I tried making a new gallery but am now having issues with loading images. It replies with an error (Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 451584 bytes) in/home/matrixph/public_html/wp-includes/media.php on line258) I called my server and they pumped up my php allocation but it still will not load images to the plugin (I can however load images elsewhere on my site).
http://matrixphoto.com.au/galleries/macritchio/
I would just like to add that I commend your work, I think this plugin is great and use it all the time on my site. I would really appreciate any help. Kind regards.