digiKam

digiKam relies on libraries such as exiv2, allowing it to edit XMP metadata embedded in images or separately as sidecar files.

digiKam also efficiently caches image thumbnails and paths in a database,[6] in the PGF format,[7] allowing for quick overviews.

As a non-modal image editor; digiKam's UI also supports live search boxes in both sidebars and the main window.

As of version 0.9 features include a GPS locator[9] and synchronization,[10] iPod Photo upload support,[11] an advanced metadata editor,[12] better support for raw image formats (using dcraw included in digiKam), full color management, a light-table,[13] pan-tool in Image Editor and Preview mode, improvements in usability, and many new plugins.

[14] Starting with version 2.0, digiKam has introduced face recognition allowing you to automatically identify photos of certain people and tag them.