Piwigo

Piwigo is a photo gallery software for the web that comes with powerful features to publish and manage your collection of pictures.

Features:

Privacy on your Photos. Make your photos private and decide who can see each of them. You can set permissions on albums and photos, for groups or individual users.
Photo Tagging. Offer your visitors another way to browse your photos, starting from the tags cloud and using multiple related tags to reduce the selection.
Browse by Date. Digital cameras store the date in the photo and Piwigo uses this date to display your photo collection in a calendar and let you browse from day to day.
Statistics and Management Tools. Administrators can browse history, process photos in batch mode, validate comments and user photos, add permalinks or manage remote servers.
Themes and Plugins. Change appearance with themes. Add features with plugins. Extensions require just a few clicks to get installed. 350 extensions available, and growing!