PNM File Documentation

Overview

Feature Value
Type Image file format
File Extensions .pbm (Portable Bitmap Image), .pgm (Portable Graymap Image), .ppm (Portable Pixmap Image)
MIME Type image/x-portable-bitmap for PBM, image/x-portable-graymap for PGM, image/x-portable-pixmap for PPM
Format Category Bitmap
Color Depth 1-bit (PBM), 8 or 16-bit (PGM), 24-bit (PPM)
Compression None (Plain Encoding) or Run-Length Encoding (RLE)
Color Models Monochrome (PBM), Grayscale (PGM), RGB (PPM)
File Structure Magic number, Width and Height, Maximum color value (not for PBM), Pixel data
Magic Numbers P1/P4 (PBM), P2/P5 (PGM), P3/P6 (PPM)
Endianess Big Endian
Metadata Support No
Transparency Support No
Multi-Page Support No
Advantages Simple format, Easy to program and convert, Supports basic image types
Disadvantages No compression (large file size), No support for modern features like layers or metadata
Used For Simple image storage, Image processing tasks, Educational purposes
ASCII (Plain) Format Human-readable (P1, P2, P3)
Binary Format Compact storage (P4, P5, P6)
Patent Status Free of patents
Creator Jef Poskanzer
First Introduced 1988
Support for Animation No