A painting tool for Mac OS X much like the old [MacPaint][1]. From the [author's website][2]:

> When Apple released the original Macintosh in 1984, they included
> two applications: MacWrite and MacPaint. Twenty-five years later,
> every Mac still includes a basic text editor in TextEdit, but a
> simple paint program is a thing of the past.
>
> Enter Paintbrush.
>
> Paintbrush can open and save to most major image formats, including
> BMP, PNG, JPEG, TIFF, and GIF. Full support for transparency is
> available for image formats that support an alpha channel (currently
> PNGs and GIFs). You can also paste images copied from many common
> Mac applications, including Microsoft Office and Apple iWork.
>
> [...]
>
> Oh, and did we mention that Paintbrush has always been, and will
> always be, completely free? (That?s both free as in gratis and free
> as in libre: the full source is distributed under an open-source
> license.)

Download #1 is version 1.2, the final Tiger-compatible version.
Download #2 is version 2.1.2, the final Leopard-compatible version.

For the latest Intel-only version, make sure to visit the author's
website. And while at it, make sure to drop them a coin or two, if you
can! There's a donation button on the side.

Compatibility
Architecture: PPC x86 (Intel:Mac)

Mac OS X 10.4 Tiger+

  [1]: http://macintoshgarden.org/apps/macpaint
  [2]: https://paintbrush.sourceforge.io/