bug#8013: 23.2.93; png not available

[Eli Zaretskii <eliz@gnu.org>]

> From: Uday S Reddy <u.s.reddy@cs.bham.ac.uk>
> Date: Thu, 10 Feb 2011 15:21:45 +0000
> Cc: U.S.Reddy@cs.bham.ac.uk
> 
> (image-type-available-p 'png) returns nil.  In the same environment,
> Emacs 23.2 and 23.2.91 return t.  But 23.2.92 and 23.2.93 are returning
> nil. 

What is your value of libpng-version?  I'd guess it's 10400 or some
such, which means you will need to install a newer version of libpng.
See this portion of README.W32:

    PNG: requires the PNG reference library 1.4 or later, which will
    be named libpng14.dll or libpng14-14.dll.  LibPNG requires zlib,
    which should come from the same source as you got libpng.
    Starting with Emacs 23.3, the precompiled Emacs binaries are
    built with libpng 1.4.x and later, and are incompatible with
    earlier versions of libpng DLLs.  So if you have libpng 1.2.x,
    the PNG support will not work, and you will have to download
    newer versions.

The latest pre-compiled binaries don't support versions of libpng
older than 1.4.0.