This file format is used as a canvas (background) in a variety of image editing software in order to set the main color of the image. It is used to fill the canvas with one solid color. It belongs to the group of 'pseudo-image' file formats. It can be used for the fill color, which is chosen from the selected area in a particular image.
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.