Professional Photo Editor Does Anyone Know A 100% Free Photo Editor That Has Good Quality?

Does anyone know a 100% free photo editor that has good quality? - professional photo editor

I like editing photos that someone can tell me to help me when a photo-editors to know really well? I have tried picnik.com and my computer will not let me save pictures after editing. I want to pay something with good image quality for professional-looking than Photoshop and / or snipshot.com without speaking. If you can help, it would be great!