Brad (The .NET Guy) @ 12/11/2002 08:31 AM
. The reason you
cannot select the compression is because PNG uses a lossless
compression system. There’s nothing to tweak, unlike JPEG (which is
lossy, and therefore you may want to balance size vs.
quality).

That’s certainly true, but zip files use lossless compression
(fortunately ;o)) and I can tweak their compression speed/size when
creating them:

-0   store only
-1   compress faster
-9   compress better

So I went looking for something that said either compression
on/off or level of compression. Of course, I don’t mind one way or
the other, but I was surprised not to get any compression when
using 24 bpp (which I was using since it ought to be smaller than
32 bpp) and I didn’t see this documented in MSDN which is the only
real reason this is of note (to me, at least).