PhotoDemon - Lightweight portable BSD licensed photo editor for Windows focused on performance and usability.
Open Camera - Open Camera is an open-source camera app for Android phones and tablets.
PixBuilder - Free Photo Editing Software for PC
Secure Camera - Modern camera app focused on privacy and security with QR & barcode scanning.
showFoto - ShowFoto is the standalone image editor of the digiKam project.
PhotonCamera - Android Camera that uses enhanced image processing.