installing gd

Hi.  I haven't used one of these lists before so sorry if I'm doing it
wrong.  I need some help installing GD.  I'm running OS X.  I'm trying to
install a shopping cart on my local machine and the installation is telling
me I need GD installed.

So I followed the installation instructions on this page:
http://www.libgd.org/DOC_INSTALL_OSX

Everything seemed to be going fine until the end when I tried to compile GD
itself.  I got this:

i686-apple-darwin9-gcc-4.0.1: /usr/X11/lib/libpng12.0.0.0.dylib: No such
file or directory
make[2]: *** [libgd.la] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

Could someone point me in the right direction?  I'm not a pro at this.