.J2K File Extension

JPEG 2000 Image

Developer Joint Photographic Experts Group
3.5  |  10 Votes
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What is a J2K file?

A J2K file is a compressed bitmap image saved in the JPEG 2000 format. It supports 16-bit color and alpha transparency and may incorporate lossy or lossless compression. J2K files typically store digital photos.

More Information

Screenshot of a .j2k file in Apple Preview 11
J2K file open in Apple Preview 11

The Joint Photographic Experts Group (JPEG) committee created the JPEG 2000 format in 2000 to replace the JPEG format. However, few applications and platforms adopted the format, and the JPEG format is still overwhelmingly favored.

There are several differences between J2K files and JPG files. For example, J2K files use wavelet compression instead of the Discrete Cosine Transform (DCT) compression used by standard .JPEG images. Also, J2K files store metadata that describes the image in the XML standard instead of the Exchangeable Image File Format (EXIF).

NOTE: JPEG 2000 images may be saved with file extensions other than .j2k. Other common extensions include .jp2 (.JP2 files) and .jpx (.JPX files).

How to open a J2K file

You can open a J2K file with various image viewing and editing applications, including:

How to convert a J2K file

Various applications, including Adobe Photoshop, CorelDRAW Graphics Suite, and Apple Preview, can convert J2K files to other formats.

For example, Adobe Photoshop can convert J2K files to many file types, including the following formats:

  • .JPG - JPEG Image
  • .PNG - Portable Network Graphic
  • .TIF - Tagged Image File Format
  • .GIF - Graphical Interchange Format
  • .WEBP - WebP Image
  • .AI - Adobe Illustrator Artwork
  • .BMP - Bitmap Image
  • .TGA - Targa Graphic
  • .PSD - Adobe Photoshop Document
  • .PDF - Portable Document Format

Programs that open J2K files

Verified by FileInfo.com

The FileInfo.com team has independently researched the JPEG 2000 Image file format and Mac and Windows apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

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