2010/2/4 Vincent Povirk <madewokherd+8cd9@gmail.com>

> * http://www.libpng.org/pub/png/PngSuite/basn4a16.png - This is a
> grayscale png with an alpha channel. That's the situation where we use
> the png_set_gray... function that was removed.

Errr.. I may actually be thinking of
http://www.libpng.org/pub/png/PngSuite/tbbn1g04.png

Those two show correctly, while the other doesn't work, but it's the image's fault, as it's only 49 B and can't be open even in other programs.
As a side note, you need to do a similar work on winemenubuilder, as it uses libpng and fails linking without modifications. to test this images i statically linked it to libpng, just to make it work, as it wasn't needed in your test.
Thank you for working on this, since i'm not really an expert on this dynamical loading code and couldn't help.