PPM (portable pixel map) is a public domain format. Portable pixel maps are written as PICTs that encapsulate 24-bit images. The PICTs are the Type 4 RGB PICTs, which is a de facto Macintosh standard.

The PPM tools on the Macintosh recognize all whitespace characters as delimiters, so PPM files can be brought directly from any other Macintosh or UNIX system and work without modification. PPM tools, are included on the 3DO Toolkit CD-ROM, which also contains several tools for converting PPM format graphics to 3DO format graphics.