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Optimize Images with CLI Tool from Google, Squoosh

There is a web application that allows us to use GUI.

However, I think many of users like a CLI tool.

What is Squoosh CLI

Squoosh CLI is an experimental way to run all the codecs you know from the Squoosh web app on your command line using WebAssembly. The Squoosh CLI uses a worker pool to parallelize processing images. This way you can apply the same codec to many images at once.

Squoosh CLI is currently not the fastest image compression tool in town and doesn’t aim to be. It is, however, fast enough to compress many images sufficiently quick at once.

GitHub logo GoogleChromeLabs / squoosh

Make images smaller using best-in-class codecs, right in the browser.


Squoosh is an image compression web app that reduces image sizes through numerous formats.


Squoosh does not send your image to a server. All image compression processes locally.

However, Squoosh utilizes Google Analytics to collect the following:

  • Basic visitor data.
  • The before and after image size value.
  • If Squoosh PWA, the type of Squoosh installation.
  • If Squoosh PWA, the installation time and date.


To develop for Squoosh:

  1. Clone the repository
  2. To install node packages, run:
    npm install
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  3. Then build the app by running:
    npm run build
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  4. After building, start the development server by running:
    npm run dev
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Squoosh is an open-source project that appreciates all community involvement. To contribute to the project, follow the contribute guide.

How to use

There are 2 ways to use it.
One is to install @squoosh/cli and the other is to use yarn/npx.

In this post, I use an image from Unsplash

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Photo by Ball Park Brand on Unsplash

First, check the image's information with identify command.
If you want to know about identify command, please check the following link.

This is before using squoosh/cli
The size is 1.42289MiB.

$ magick identify -verbose ball-park-brand.jpg
  Filename: ball-park-brand.jpg
  Format: JPEG (Joint Photographic Experts Group JFIF format)
  Mime type: image/jpeg
  Class: DirectClass
  Geometry: 3788x2525+0+0
  Resolution: 72x72
  Print size: 52.6111x35.0694
  Units: PixelsPerInch
  Colorspace: sRGB
  Type: TrueColor
  Base type: Undefined
  Endianness: Undefined
  Depth: 8-bit
  Channel depth:
    Red: 8-bit
    Green: 8-bit
    Blue: 8-bit
  Channel statistics:
    Pixels: 9564700
      min: 0  (0)
      max: 255 (1)
      mean: 132.878 (0.521092)
      median: 100 (0.392157)
      standard deviation: 58.4716 (0.2293)
      kurtosis: -0.537623
      skewness: 0.717458
      entropy: 0.891271
      min: 0  (0)
      max: 255 (1)
      mean: 148.547 (0.582538)
      median: 166 (0.65098)
      standard deviation: 44.0201 (0.172628)
      kurtosis: 2.17474
      skewness: -1.58907
      entropy: 0.85256
      min: 0  (0)
      max: 255 (1)
      mean: 116.84 (0.458195)
      median: 151 (0.592157)
      standard deviation: 56.4098 (0.221215)
      kurtosis: -0.519711
      skewness: -1.03088
      entropy: 0.838754
  Image statistics:
      min: 0  (0)
      max: 255 (1)
      mean: 132.755 (0.520608)
      median: 139 (0.545098)
      standard deviation: 52.9672 (0.207714)
      kurtosis: 0.100211
      skewness: -0.475699
      entropy: 0.860862
  Rendering intent: Perceptual
  Gamma: 0.454545
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Matte color: grey74
  Background color: white
  Border color: srgb(223,223,223)
  Transparent color: none
  Interlace: JPEG
  Intensity: Undefined
  Compose: Over
  Page geometry: 3788x2525+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: JPEG
  Quality: 73
  Orientation: Undefined
    Profile-icc: 524 bytes
    date:create: 2021-04-11T15:06:21+00:00
    date:modify: 2021-04-11T15:00:28+00:00
    icc:copyright: IX
    icc:description: c2
    jpeg:colorspace: 2
    jpeg:sampling-factor: 2x2,1x1,1x1
    signature: f74c895b9e40fba1656729d620ccb1d964d0a8d44c48f9f755b4e468a7503885
    verbose: true
  Tainted: False
  Filesize: 1.42289MiB
  Number pixels: 9564700
  Pixels per second: 12.8035MP
  User time: 0.740u
  Elapsed time: 0:01.747
  Version: ImageMagick 7.0.11-6 Q16 x86_64 2021-04-03
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Let's try squoosh/cli. In this post, I will try two thing. One is to use options and the other is auto.

  • --mozjpeg: Use MozJPEG to generate a .jpg file with the given configuration

  • '{quality:50}': image quality

  • -d out: create a dir and store an optimized image

  • ball-park-brand.jpg: source image

$ squoosh-cli --mozjpeg '{quality:50}' -d out ./ball-park-brand.jpg
1/1 ✔ Squoosh results:
 ./ball-park-brand.jpg: 1.42MB
  └ .jpg  → 390.01KB (26.8%)
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The file size is 390.01KB.
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$ squoosh-cli --mozjpeg auto ./ball-park-brand.jpg
1/1 ✔ Squoosh results:
 ./ball-park-brand.jpg: 1.42MB
  └ .jpg  → 1.53MB (107%) using --mozjpeg '{quality:89.0625}'
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The file size is 1.53MB 😂 😂 😂
However, right now I don't recommend you to use auto because you use squoosh to reduce the file size but the size increased lol.

In addition, the process with auto takes so much time(10 min) which isn't reasonable.

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comparison identify results

The left is the original and the right is the optimized image info.

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If you are looking for tools for web dev, please check this article!

Top comments (6)

crunchpbn profile image

Hello, I am an online squoosh user but I would like to use it for image batches. However, I don't have any notion of development or use of the terminal. Can you tell me how to install and use the CLI version, it is not clear to me.
Thanks to you

0xkoji profile image

Here is the installation guide

If you don't have npm, you need to install nodejs.

langtuhodo profile image
Chiasefree Dot Com

I have a folder image ~10k file including jpg, png and how to compress jpg images in that folder? and does not affect the rest of the image formats. PLease help me. Thanks

0xkoji profile image
langtuhodo profile image
Chiasefree Dot Com

I tried it and it doesn't compress any format. For example, if I have files like jpg, png, webp located in the same folder, I want to compress only jpg files in that folder and not png, webp.

Thread Thread
0xkoji profile image

Did you run the command with the right options and the target(*.jpg) correctly?