I just recently switched from pngout (non-free) to zopflipng. So I kinda use it almost daily now, but not for a very long time. I also evaluated pngcrush and optipng (which are included in Debian as well) but except when zopflipng is messing with the color mode, it always produces smaller files than the other tools.
While you are asking, there seems to be a similar issue when you have some special kind of palette [1], preventing zopflipng from optimizing the image. My fix doesn't help there, and I didn't look into it yet. There are more issues on GitHub that haven't been addressed by upstream. But so far none, that I personally care too much about. [1]: https://github.com/google/zopfli/issues/75 On Wed, May 10, 2017 at 7:29 PM, László Böszörményi (GCS) <g...@debian.org> wrote: > Control: merge 862286 862287 > > Please file bugs only once. > > On Wed, May 10, 2017 at 6:07 PM, Sebastian Noack > <sebastian.no...@gmail.com> wrote: >> Thanks for adding zopflipng to the package. However, I just found one >> scenario in which it gives undesirable results. > [...] >> So I wonder if you would consider adding patches to fix bugs like this >> to the Debian package? For this particular bug, you find the patch (it >> is a tiny change) inline in my comment on the upstream issue. > I had the impression you use zopflipng daily before asking for its > inclusion. OK, never mind. Do you have any bugs that needs to be > fixed? It would be nice to include all in one shot and not one after > another. > > Regards, > Laszlo/GCS