mtPaint is a lightweight open source paint application for Linux and Windows. It is is aimed at creating indexed palette images and pixel art, and is designed to be simple and easy to use.
While the last stable mtPaint version was released back in 2011, there have been quite a few development releases since then, with the last one dating to June, 2016. I couldn’t find a PPA with the latest mtPaint 3.50 development releases, so I created one to make it easy to install in Ubuntu and Linux Mint.