I've been using ZenPhoto for hosting a family photo gallery where all family members can sign in and upload and share their photos, and if I create a new directory in /var/www/zenphoto/albums/user1/my_new_album/, and add some pictures to it, ZenPhoto automatically recognizes them and displays the album with photos and video on the website.  This makes it really nice to copy/paste photos in bulk using FTP, since we don't have to open a browser and click "upload".

Are there any solutions that exist?  Does anybody have a recommendation for how they would import several thousands pictures from a dozen different users?

Thanks in advance for any information.