PhotoDemon - Lightweight portable BSD licensed photo editor for Windows focused on performance and usability.
PanoramaCrop for Instagram - PanoramaCrop for Instagram is a free photography app that allows you to easily splits your wide photos so you can make the most out of the new Instagram’s multi-photo images, created and published by Muffin.
PhotoFlare - Quick, simple but powerful Cross Platform image editor.
King Camera - Cam 360 Selfie Camera, King Camera is one of best, a professional selfie camera app that takes beautiful selfies in seconds with effects filters.
showFoto - ShowFoto is the standalone image editor of the digiKam project.
Cool Gram - $5 a month makes your IG officially cool.