http://prdownloads.sourceforge.net/optipng/optipng-0.6.4.tar.gz?download Latest version: OptiPNG 0.6.4 (released on 15 Mar 2010). It might solve bug 308673 but unsure.
Version 0.6.4 14-mar-2010 ------------- + Upgraded libpng to version 1.4.1-optipng [private]
fixy!