PhotoFlare - Quick, simple but powerful Cross Platform image editor.
Polarr Photo Editor 3 - The most powerful photo editor in the web.
PixBuilder - Free Photo Editing Software for PC
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
PhotoDemon - Lightweight portable BSD licensed photo editor for Windows focused on performance and usability.
IMG.LY - Power Your Apps with IMG.LY | The Leading Provider of Design, Photo, and Video Editing SDKs