miikah/imagemagick-jxr repository overview

Docker image for https://github.com/ImageMagick/ImageMagick⁠

Originally this image added -q and -Q options to be passed to the JXR encoder. Latest ImageMagick versions pass -q as-is, so now main difference with this image is that it also passes -Q option so that alpha channel quantization can be controlled with the same quality argument. Regular ImageMagick always uses lossless encoding for JXR alpha channel.

For .jxr encoder, use quality between 1and 255 (from lossless to worst quality). Generally values like 30 are fine for regular images while 128 is fine for HDR.

Usage to re-encode existing .jxr image with 50% quality in active directory

docker run --rm -v $PWD/:/imgs miikah/imagemagick-jxr image.jxr -quality 128 jxr_out_128.jxr

Or using mogrify to batch convert all .tiff images in active directory to .jxr

docker run --rm -v $PWD/:/imgs miikah/imagemagick-jxr mogrify -format jxr -quality 25 *.tiff