Did you add a (previously uploaded) image before (trying to) save the gallery?
Did you enable sitewide cookies in gsconfig?
PS It's better to post questions in this plugin's support forum: http://get-simple.info/forum/topic/1882/i18n-gallery/
Did you enable sitewide cookies in gsconfig?
PS It's better to post questions in this plugin's support forum: http://get-simple.info/forum/topic/1882/i18n-gallery/