.PNJ File Extension

Portable Network JPEG Image

Developer PNG Development Group
2.2  |  5 Votes

What is a PNJ file?

A PNJ file is an image saved in the Portable Network JPEG (PNJ) format. PNJ files are similar to normal .JPG files, in that they contain image data compressed using lossy compression. However, unlike typical JPGs, PNJ files can contain transparent sections.

More Information

The PNJ format is a hybrid of the .PNG and JPEG formats. Each PNJ file contains JPEG-encoded image data saved within a PNG container. This allows PNJ files to include an alpha channel, like PNG files, while still being compressed using lossy compression (reducing their file size in comparison to PNG files).

The PNG Development Group created the PNJ format for use alongside the .MNG (Multiple-Image Network Graphic) format. Each MNG file can be comprised of multiple PNJ files, used to show an animation. However, both MNG files and PNJ files are quite uncommon. Thus, most image viewers and editors cannot open PNJ files.

NOTE: During development of the MNG format, the PNG Development Group renamed the PNJ format to the JPEG Network Graphic (.JNG) format.

How to open a PNJ file

You may be able to open a PNJ file with XnViewMP. While XnViewMP does not officially support the PNJ format, it can open many types of image files, including .JNG files (to which PNJ files are related).

At this time, there is no known program that officially supports the PNJ format.

Open over 400 file formats with File Viewer Plus.Free Download

Programs that open PNJ files


Verified by FileInfo.com

The FileInfo.com team has independently researched the Portable Network JPEG Image file format and Mac, Windows, and Linux apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

If you would like to suggest any additions or updates to this page, please let us know.