Great option to other image editors and image creating software. It has a simple and intuitive user interface, yet supports both layers and 3D objects. Functional across all major OS. It is free, as in open source. It imports .PDN files created with Paint.NET without issues.
GIMP - GIMP is a multiplatform photo manipulation tool.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
Microsoft Paint - Paint (formerly Paintbrush) is a simple, ultra-basic graphics painting program that is included...
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.