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).