Losslessly Optimising Images

• oxipng

  14 2,618 8.0 Rust

  Multithreaded PNG optimizer written in Rust

I wonder how `pngcrush` compares to `oxipng` (https://github.com/shssoichiro/oxipng).

Personally, I use `oxipng` if I want lossless compression. However, most of the time, I use `pngquant` instead, since it gives significant size reduction even at `99%` (I can't even distinguish between the original and reduced image).

    pngquant --quality=99 --ext=.png --force file.png

• shrivel

  2 5 10.0 C#

  Command line wrapper utility to shrink a path of images for web based on external tools.

• InfluxDB

  www.influxdata.com sponsored

  Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.

  

• libavif

  44 1,370 9.7 C

  libavif - Library for encoding and decoding .avif files

  

• ImageOptim

  83 8,932 7.9 HTML

  GUI image optimizer for Mac

  

• jpeg2png

  2 469 10.0 C

  silky smooth JPEG decoding

This tool optimises blocky JPEGs for a better viewing pleasure: https://github.com/victorvde/jpeg2png

> jpeg2png finds the smoothest possible picture that encodes to the given JPEG file.

• squoosh

  266 20,944 5.8 TypeScript

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

  

I am a bit surprised that no one has mentioned https://squoosh.app/ yet

• guetzli

  10 12,881 0.0 C++

  Perceptual JPEG encoder

  

I've never had much luck using jpegoptim. In most cases it's only removing the metadata, which isn't much on high-res files.

Guetzli is nice, if you don't have too many images to recompress (quite slow): https://github.com/google/guetzli

• WorkOS

  workos.com sponsored

  The modern identity platform for B2B SaaS. The APIs are flexible and easy-to-use, supporting authentication, user identity, and complex enterprise features like SSO and SCIM provisioning.

  

• ImageOptim-CLI

  1 3,418 5.4 TypeScript

  Make optimisation of images part of your automated build process

Disclaimer: There may be newer tools with better support for Linux or Windows, but for macOS users, the venerable "ImageOptim-CLI" project ^1 remains a powerful option.

It wraps ImageOptim, ImageAlpha, and JPEGmini in a single executable, and is able to produce visually-indistinguishable image assets with 60-80% reduction in bytecount, for nearly any corpus of unoptimized files. I've used it to great effect as a webperf consultant. Enjoy! :)

1. https://github.com/JamieMason/ImageOptim-CLI

• zopfli

  8 3,368 2.6 C++

  Zopfli Compression Algorithm is a compression library programmed in C to perform very good, but slow, deflate or zlib compression.

  

zopflipng typically beats pngcrus and optipng (on Linux at least) but by default it drops auxillary PNG chunks [0] which can result in browsers (and other applications) using a different color space, causing the resulting images to look more washed out than the original. To prevent this you need to explicitly pass --keepchunks=cHRM,gAMA,pHYs,iCCP,sRGB,oFFs,sTER to zopflipng.

Unfortunately it (and most other tools) don't have APNG support, keeping only the first frame.

[0] https://github.com/google/zopfli/issues/113

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