PngSuite - Zlib compression / PNG-files
(using Netscape embed-tags)
z00n2c08 - color, no interlacing, compression level 0 (none)
z03n2c08 - color, no interlacing, compression level 3
z06n2c08 - color, no interlacing, compression level 6 (default)
z09n2c08 - color, no interlacing, compression level 9 (maximum)
Willem van Schaik, Singapore, May 1996
http://mht3.gintic.gov.sg:8000/WWWillem.html