FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
Piwigo.org - Manage your photo collection with Piwigo. Piwigo is open source photo gallery software for the web. Designed for organisations, teams and individuals.
digiKam - Professional Photo Management with the Power of Open Source
novaGallery.org - Beautiful php image gallery - easy to use, with modern responsive design, private mode, themes, languages
FastPictureViewer - A hardware-accelerated image viewer for the modern Windows platform.
PhotoStructure - PhotoStructure is a complete photo and video management application designed for the whole family.