Lossless Image Compressions using Docker

I tried couple of existing docker containers to compress images without success. Both suffered a sever security threat because of being ‘very old’. There was only one complete tool zevilz/zImageOptimizer and that too didn’t have docker (have sent a pull request) meaning that you have to install everything for the compression.

I turned it into docker image over  varunbatrait/zimageoptimizer

My primary requirement was to use this image to shrink images every week or a fortnight on few blogs or images shot by my camera.This docker image is ideal for that.

It supports cron and as a web user compressing images helps in saving your BW and thus contribute you scalability.

Supported Format

  1. JPEG
  2. PNG
  3. GIF

How to use?

There are two ways to do it:

Maintain the marker

Marker is just a file with a timestamp of last run command. If new images are added, zImageOptimizer will consider only new image.

docker run -it -u "$UID:$GID" -d --volume /mnt/ImagesHundred/marker:/work/marker --volume /mnt/ImagesHundred/images/:/work/images/ -v /etc/passwd:/etc/passwd:ro -v /etc/group:/etc/group:ro varunbatrait/zimageoptimizer ./zImageOptimizer.sh -p /work/images/ -q -n -m /work/marker/marker

Not Maintaining the marker

docker run -u "$UID:$GID" --volume /path/to/images:/work/images -v /etc/passwd:/etc/passwd:ro -v /etc/group:/etc/group:ro  varunbatrait/zimageoptimizer


  1. Images are losslessly compressed – no quality loss.
  2. You don’t have to install dependencies on every server. It is in docker.
  3. You can use it with cron.

Pain with PNGs

Please note that PNGs images can take significant time (15-25 seconds per image) and CPU (almost 100%). Just stay calm! 🙂

Worth Sharing?


  1. My images are now serving fast and crisp. Everyother solution like on-fly has a flaw related to CPU or Double Memory. This is perfect

  2. This is by far the most important post in the world wide web. I was searching for solution for days. I am new to docker and hence wasn’t able to find it. I am so thankful for this solution. I ran it overnight, saw results, searched back this article again just to say THANK YOU!

  3. Hi, I find it very nice solution. I had to break down various folders and assign it to different docker containers to enjoy full CPU.

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