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Comment by FooBarWidget | Hacker News Reader

What? I thought zip and png use the same compression algorithm.

They do indeed.

If you're seeing BMP+ZIP being smaller than PNG it only means your PNG encoder is poor. This can be easily fixed with a PNG optimizer like Zopfli, AdvPNG or OptiPNG.

zopfli: not a png optimizer.

Well, zopflipng is! https://code.google.com/p/zopfli/source/browse/README.zopfli...

I've had the best luck using opitpng and then pngout.

https://github.com/ajslater/picopt ...will do this automatically for you.

Pictopt: A multi-format, recursive, multiprocessor aware, command line image optimizer utility that uses external tools to do the optimizing.

For an all in one GUI for Mac approach to this, try ImageOptim

PNGOut is definitely better than OptiPNG most of the time:

http://www.olegkikin.com/png_optimizers/

zopflipng (with -m switch) is close to or better than the best on those five images:

    1_zopflipng.png  8.466
    2_zopflipng.png 18.739
    3_zopflipng.png  8.012
    4_zopflipng.png 91.879
    5_zopflipng.png  1.117

Yes, I even mentioned that.

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