RIG is a web-based JPEG image album viewer, especially useful for digital camera albums; provides automatic image resizing, preview & thumbnail caching, user authentication; composed of a PHP web interface and a C++ thumbnail engine.
LinPHA is an easy to use, multilingual, flexible photo/image archive/album/gallery written in PHP. It uses a SQL database to store information about your pictures. It comes with a HTML based installer, so you don't need experience in setting up SQL