Free image organizers

digiKam is a free and open-source image organizer and tag editor written in C++ using the KDE Frameworks.

F-Spot is a discontinued image organizer, that was designed to provide personal photo management for the GNOME desktop environment. The name is a play on the word F-Stop. F-Spot can be used for basic photo editing and management.

Photo manager for GNOME

gThumb is a free and open-source image viewer and image organizer with options to edit images. It is designed to have a clean and simple user interface and follows the GNOME Human Interface Guidelines and integrates well with the GNOME desktop environment.