yappa-ng is a very powerful but easy to install and easy to use online PHP photo gallery for all Operating Systems (Linux/UNIX, Windows, MAC, ...), and all Webservers (Apache, IIS, ...) with no need for a DataBase (no MySQL,...).yappa-ng is prone to a security vulnerability in the AddOn that shows a random image from any homepage. This issue may let unauthorized users access images from locked albums.http://www.securityfocus.com/bid/11314