Image::ExifTool::JPEGDigest(3) User Contributed Perl Documentation Image::ExifTool::JPEGDigest(3)

# [NAME](#NAME)

Image::ExifTool::JPEGDigest - Calculate JPEGDigest and JPEGQualityEstimate

# [SYNOPSIS](#SYNOPSIS)

This module is used by Image::ExifTool

# [DESCRIPTION](#DESCRIPTION)

This module contains a lookup for values of the JPEG DQT digest, allowing some image identification from JPEG data alone. It also calculates an estimated JPEG quality if requested.

# [AUTHOR](#AUTHOR)

Copyright 2003-2026, Phil Harvey (philharvey66 at gmail.com)

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

# [REFERENCES](#REFERENCES)

<https://github.com/ImageMagick/ImageMagick/blob/master/coders/jpeg.c>

# [ACKNOWLEDGEMENTS](#ACKNOWLEDGEMENTS)

Thanks to Jens Duttke for most of the work that went into this module, and to Franz Buchinger for the values he added.

# [SEE ALSO](#SEE_ALSO)

"JPEG Tags" in Image::ExifTool::TagNames, [**Image::ExifTool**(3pm)](/man/os/exiftool/Image::ExifTool.3pm)

2026-10-09 perl v5.44.0

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Document: Image::ExifTool::JPEGDigest(3pm) from exiftool 13.59-r3 (Chainguard OS)
Source: https://github.com/exiftool/exiftool