Milton

Milton is a free and open-source infinite canvas paint program. You can paint with (almost) infinite detail.

It feels raster-based but it works with vectors. Your work is always saved automatically. There is no need for a save button. Milton files are very small.

It offers unlimited undo, layers, export to JPEG or PNG at any resolution your machine supports. It is not an image editor. It is not a vector graphics editor. It is a program that lets you draw, sketch and paint