[tc4me]

Paint.NET is BASED but unfortunately it's not open source so by default it infringes on my rights and beliefs.
GIMP is okay if you're doing actual photo editing like anything regarding filters or manipulation of an existing image, but even their own docs say that it's not for drawing: https://docs.gimp.org/en/gimp-using-rectangular.html

For drawing, they recommend Inkscape but that's too oriented for vector graphics (i.e. it's an Adobe Illustrator alternative instead of a Photoshop alternative)
Personally, the best opensource free paint software I've come across is Krita. The UI is gorgeous, has like 90% of the same features Photoshop has, is more lightweight in terms of CPU and RAM usage (not to mention install size) and works perfectly cross-platform for all the Windows kids.

But I just use Clip Paint Studio since I got it on sale for 25$ (every three months or so) and it's more oriented towards drawing animays and their community resource repository for brushes and whatnot is f*** HUGE (not to mention free 10GB cloud storage for your assets and drawings)

Paint.NET is no longer open source, but freeware. 

that is a purely political difference

Why "Open Source" misses the goal of Free Software is a more current and better version of this article. For historical reasons, we leave this article.

Although free software would give you the same freedom under a different name, it makes a big difference what name we use: different words convey different ideas.

In 1998, some in the free software community began using the term “open source software” instead of free software to describe what they were doing. The term “open source” was quickly associated with a different approach, philosophy, values, and even other criteria for which licenses are acceptable. The free software and open source movements are now independent movements with different views and goals, although we are working together on some projects.

The main difference between the two movements lies in their values, their views of the world. For the open source movement, the question of whether software should be open source is a practical question, not an ethical one. Someone put it this way: "Open source is a development methodology, free software is a social movement." Non-free software is a suboptimal solution for the open source movement. Non-free software is a social problem for the free software movement, and free software is the solution.