PNM (Portable anymap)

A PNM file is an image file format used to store color images in a simple binary format and was used in many applications when it was first introduced.

The format stores image pixel data as a sequence of bytes and does not use any compression, meaning there is no loss in quality when saving an image in the PNM format. The use of uncompressed binary does mean that PNM files can become very large at higher resolutions.