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Mozjpeg's gain come partly from using progressive JPEG encoding, which is also available in libjpeg-turbo. See the post http://www.libjpeg-turbo.org/About/Mozjpeg from libjpeg-turbo's author. And actually, the photo_3.jpg picture in the blog-post is progressive jpeg. So the command line for a fair comparison should probably be: jpegtran -outfile out.jpg -optimise -copy none -progressive in.jpg

Thanks for pointing this out. I went back in and checked and I was using the -progressive option on the jpegtran command and so the comparison was done with -progressive.

However, when I generated the image in the blog post I didn't do that and so I have rerun it. Updating the blog post now.

oh, ok. Thanks for the update!

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