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.
PGM is a storage format for grayscale images. Files in this format can be opened using software: ACDSee Photo Manager 14, ACD Systems Canvas 15, Corel PaintShop Pro X4. This type of file can be edited with a text editor. PGM files can be in two versions: P2 / P5. P2 are readable, P5 - to binary formats.