Crunch - Insane(ly slow but wicked good) PNG image optimization

•    Python

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Crunch is a tool for lossy PNG image file optimization. It combines selective bit depth, color type, and color palette reduction with zopfli DEFLATE compression algorithm encoding using the pngquant and zopflipng PNG optimization tools. This approach leads to a significant file size gain relative to lossless approaches at the expense of a relatively modest decrease in image quality (see example images below). Historical benchmarks with the files included in Cédric Louvrier's PNG Test Corpus versus other commonly used PNG optimization software are available in BENCHMARKS.md.

png png-compression compression image-quality image-processing images image image-compression pngquant zopflipng lossy lossy-compression

pngquant - Command-line utility and a library for lossy compression of PNG images

•    C

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pngquant is a PNG compressor that significantly reduces file sizes by converting images to a more efficient 8-bit PNG format with alpha channel (often 60-80% smaller than 24/32-bit PNG files). Compressed images are fully standards-compliant and are supported by all web browsers and operating systems.

palette png png-compression conversion smaller stdin image-optimization quantization image-library

mediancut-posterizer - Lossy PNG compressor for RGBA PNGs

•    C

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Reduces number of distinct color/alpha intensities in the image. Unlike typical posterization, which distributes levels evenly, this one tries to pick levels intelligently using varaince-based Median Cut and Voronoi iteration. The goal of this tool is to make RGB/RGBA PNG images more compressible, assuming that lower number of unique byte values increses chance of finding repetition and improves efficiency of Huffman coding.

png-compression lossy png minification image-optimization

optimise-images - Batch image resizer, optimiser and profiler using ImageMagick convert, OptiPNG, JpegOptim and optional ZopfliPNG, Guetzli and MozJPEG

•    Shell

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Batch jpg, jpeg and png image resizer, optimiser and image profiler using ImageMagick convert, OptiPNG, JpegOptim and optional Mozilla MozJPEG, ZopfliPNG and Google Guetzli (work in progress for Guetzli). Profile original images via script's profile flag and pass the directory path to the directory containing the images you want to optimise /home/nginx/domains/domain.com/public/images. This is your baseline to compare resizing and optimisations applied to images using above default variable parameters.

zopflipng optipng jpegoptim png jpg jpeg imagemagick image-resizer webp optimize-images lossless-images image-quality image-conversion resize-images png-compression png-optimization png-optimizer guetzli mozjpeg jpegtran