CartaPGM is a plug-in for Photoshop on Macintosh that reads and writes files in the Portable Gray Map (PGM) format.

CartaPGM writes the following formats:

  • PGM 8-bit grayscale images
  • PGM 16-bit grayscale images

CartaPGM reads the following formats:

  • PGM 8-bit grayscale images
  • PGM 16-bit grayscale images
  • PBM 1-bit black and white images
  • PPM 24-bit RGB color images


You can download CartaPGM here for free.


Decompress the ZIP file and drag the plug-in to the Plug-Ins folder in the Photoshop application folder.


Once the plug-in is installed, open PGM, PBM or PPM files with the normal File - Open menu command. To write files in the PGM format, use File - Save and select Portable Gray Map (PGM) in the Format menu.

Known limitations

CartPGM only runs on Macintosh.
CartaPGM does not run on Mac OS X 10.5 or on old 68k Macs.
CartaPGM cannot write PGM files in 16 bit mode with Photoshop version 4 (the other file formats with PS 4 are supported).
CartaPGM probably doesn't work with Photoshop prior to version 4.


CartaPGM is based on Pascal Lamboley's pbm plug-in ( He generously shared essential code for this project. You can download his plug-in here. It runs only in classic mode - but unlike CartaPGM, it can write files in the following formats: PPM (24-bit RGB), PBM (1-bit black and white), and PGM 8 bit binary. Cartagena was developed by Bernhard Jenny (


CartaPGM is copyrighted by Pascal Lamboley and Bernhard Jenny. CartaPGM may be freely distributed, as long as no party makes profit from its distribution. But we hope you can make a profit on it's use.

If you cannot live without it, send a postcard or some CDs with classical music to:

Pascal Lamboley
102 chemin de la Peyrette
31170 Tournefeuille