Jpeg quality comparison of Photoshop and Imagemagick

Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
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magick
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Re: Jpeg quality comparison of Photoshop and Imagemagick

Postby magick » 2009-03-30T10:18:29-07:00

Yes its normal for Photoshop to produce higher quality JPEG images. They create their own optimized DCT coefficients whereas we use the default one provided by the JPEG delegate library. We have no immediate plans to improve the quality of the JPEG produced by ImageMagick.

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Re: Jpeg quality comparison of Photoshop and Imagemagick

Postby NicolasRobidoux » 2011-04-02T14:52:10-07:00

Has this changed? (Have the delegate libraries gotten better?)

http://blog.endpoint.com/2009/12/jpeg-compression-quality-or-quantity.html suggests that the difference is not that big. On the other hand, some other recent posts suggest that IM is still somewhat inferior w.r.t. JPEG.

Would it be possible to improve matters by, say, combining quantization with lossless or lossy JPEG compression (for thumbnails, esp.)? (I imagine this is hugely complicated.)

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Re: Jpeg quality comparison of Photoshop and Imagemagick

Postby magick » 2011-04-02T15:11:40-07:00

We're always looking for improvements in image quality. If you would like to contribute in this area, please do. We're currently looking toward ImageMagick 7 (see http://www.imagemagick.org/Usage/bugs/I ... ations.txt) which leaves us little time to investigate JPEG quantization improvements.


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