Convert sfw to pgm

What is the difference between .sfw and .pgm?

Description: The SFW file format is associated with Seattle FilmWorks, a photography and film processing company. It was primarily used for images that were developed and digitized by Seattle FilmWorks. The format was proprietary, meaning it required specific software provided by Seattle FilmWorks or compatible third-party applications to view or convert the images. SFW files were popular in the late 1990s and early 2000s, especially among consumers who used Seattle FilmWorks' mail-order film developing service.; A PGM file is a grayscale image file saved in the portable gray map (PGM) format and encoded with one or two bytes (8 or 16 bits) per pixel. It contains header information and a grid of numbers that represent different shades of gray from black (0) to white (up to 65,536). PGM files are typically stored in ASCII text format, but also have a binary representation.