Converting PNG to B/W (1 bit color)

From: Lars Black (lcb)
Date: 10/27/04 

Date: Wed, 27 Oct 2004 23:51:43 +0200

I need to convert a PNG 256 color file to B/W format, is there a free
library available that can handle that?
It's the only PNG manipulation that I need to do, so it doesn't have to be a
very fancy library..

Cheers,
Lars