MyPaint

The frame tool puts a defined output area around an otherwise unlimited canvas. Its size controls accept pixels and physical units, so a loose collection of sketches can become a bounded image without changing how the canvas scrolls.

OpenRaster keeps a working document’s layers for continued editing or exchange with compatible applications. PNG and JPEG provide a rendered image. For developing alternatives, Save As Scrap creates numbered draft files in a dedicated folder; later revisions become separate scraps.

Use the repository’s stable-release download for ordinary work. It also publishes development builds, but explicitly warns that alpha versions can crash. The painting tools include freehand strokes, layer groups and a brush system that stores brush settings with strokes.