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Optimize Images with CLI Tool from Google, Squoosh

Koji (he/him)
Never lose curiosity Software Engineer in NYC/Research Resident@NYU-ITP18-19 Mostly I work with typescript, javascript, react, and python. code to do something weird/useless/helpful
・4 min read

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 allows you to dive into the advanced options provided by various image compressors.


Squoosh now has a CLI that allows you to compress many images at once.


Google Analytics is used to record the following:

  • Basic visit data.
  • Before and after image size once an image is downloaded. These values are rounded to the nearest kilobyte.
  • If install is available, when Squoosh is installed, and what method was used to install Squoosh.

Image compression is handled locally; no additional data is sent to the server.

Building locally

Clone the repo, and:

npm install
npm run build
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You can run the development server with:

npm run dev
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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!

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