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

pornel · on July 15, 2014

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.

ajslater · on July 16, 2014

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

imaginenore · on July 16, 2014

PNGOut is definitely better than OptiPNG most of the time:

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

jibsen · on July 16, 2014

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

Hello71 · on July 16, 2014

zopfli: not a png optimizer.

chadaustin · on July 16, 2014

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

panzi · on July 15, 2014

Yes, I even mentioned that.