What are some alternatives?
When comparing Microsoft Paint and JS Paint, you can also consider the following products
GIMP - GIMP is a multiplatform photo manipulation tool.
KiddoPaint - MS Paint in your browser (with emojis 💃😽🎨)
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.
More Moji in Slack - You don't have enough emojis in Slack.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Paint.NET - Paint.NET is a free image and photo editing software.