This format is used as the color palette format for a variety of operating system image editors. It is used to store font templates in text and graphic editors. It allows you to change color intensity and transparency levels.
PPM is a simple format for storing images portable pixmap: color (PPM), grayscale (PGM) and black and white (PBM). These formats can provide an intermediate representation of the data when converting raster image files listed three types between different platforms. PPM format was developed by Jeff Poskanzerom.