What are some alternatives?
When comparing Microsoft Paint and Krita, you can also consider the following products
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.
Paint.NET - Paint.NET is a free image and photo editing software.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Pinta - Simple cross-platform image editing software.