Paint.net is a free and very capable image editing software for Windows. Great alternative to Photoshop for people that do not need all the stuff PS offers.
Free Personal • Proprietary
What is Paint.NET?
Paint.NET is a free image and photo editing software. It features an intuitive and innovative user interface with support for layers, unlimited undo, special effects, and a wide variety of useful and powerful tools. An active and growing online community provides friendly help, tutorials, and plugins.
The app is completely free through a direct download on the website, though there is a small fee involved for access to the app through Windows Store.