PKM is the native graphics format of classic versions of the GrafX2 paint software.
GrafX2 was originally a DOS program developed by Sunset Design. It was ultimately made open source, taken over by other developers, and ported to other platforms.
Files start with ASCII "
PKM". The fourth byte is a format version number, and is probably always
- Refer to the TECH_ENG.TXT file included with DOS versions of the software.