showFoto - ShowFoto is the standalone image editor of the digiKam project.
Pixel Pix - Turn your photos into pixel art
PhotoFlare - Quick, simple but powerful Cross Platform image editor.
Trixel - Instagram for triangular pixel art
PhotoDemon - Lightweight portable BSD licensed photo editor for Windows focused on performance and usability.
PictureThat - Fill your walls with art and photos in AR 🎨