I will have a look in one month...
Please ask again if you do not have any answer.
Every first display of gallery (as an administrator - for guest it works fine) I get an error notice from AdditionalPages:
Notice: Undefined index: section in C:\Program Files\VertrigoServ\www\piwigo\plugins\AdditionalPages\main.inc.php on line 37
Any clue what is it about?