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pngquant versus optipng and pngcrush, a PNG benchmark

Measured file sizes and timings on real server hardware.

Answers
Which PNG optimiser is fastest, optipng, pngcrush or pngquant?
Topics
cloud · data · howto · networking · programming · server · web · webdesign · work
Full article on willem.com
https://willem.com/en/2018-09-26_optimising-images-for-the-web-and-performance/

Summary

pngquant won my 2018 benchmark by a wide margin: it shrank a 2897KB test image to 744KB in 5.2 seconds, where optipng and pngcrush needed minutes to reach only 2510KB. It is lossy, but I could not see the difference.

Full text

The test ran on a quad-core Intel Xeon server with 8GB RAM, using a heavy 2897KB test image with mixed content (photo, text and solid colours), standing in for the thousands of PowerPoint slides one customer site serves as PNG. optipng at its extreme -o7 setting reached 2510KB in 2 minutes 36 seconds, its defaults 2536KB in 4.9 seconds. pngcrush -brute also reached 2510KB, in 1 minute 42 seconds, defaults 2531KB in 9.2 seconds. pngquant produced 744KB in 5.2 seconds at its extreme setting and 746KB in 4.2 seconds by default. pngquant uses a different, lossy algorithm, so a little quality is traded away, but comparing closely I could not spot the difference. For automated server-side optimisation it was the clear choice.

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