RawTherapee - RawTherapee is a free RAW converter and digital photo processing software.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Darktable - darktable is an open source photography workflow application and raw developer.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
digiKam - Professional Photo Management with the Power of Open Source
Corel AfterShot Pro - Say hello to Corel AfterShot Pro 3, the world’s fastest photo workflow tool! Edit your photos up to 4x faster than Lightroom so you can spend more time behind the camera. Download a free 30-day trial today!