About the Second Edition

Despite its public release more than four years after the publication of the first (paper) edition, this electronic version is fundamentally still a 1999 publication. That is, the updates and modifications that go beyond basic formatting and legal issues have been limited almost entirely to details that could have (or should have) been in the original. These include the addition of missing index entries and the lists of figures and tables, correction of numerous typos and other errata, restoration of color figures (using the original images!), and so forth. A handful of URLs have also been updated, but only those associated with the PNG home site and its close relatives (such as the zlib home site).

More specifically, the lists of applications with PNG and MNG support are woefully out of date, as are many (if not most) of the URLs and the specific nature of the support. Not only would updating them have required a huge investment in time, it also would have been completely redundant; the PNG and MNG home sites contain nearly complete lists of applications with PNG and MNG/JNG support, and they are updated regularly. Thus each chapter simply contains a link to the appropriate ``live'' web pages on libpng.org.

Note that I (Greg Roelofs) do intend to perform further updates as time permits, but these will not truly constitute a ``second edition'' in the usual sense. However, the Free Software Foundation is interested in publishing a fully updated edition of the book, so keep an eye on their site if you're interested.