Bug 5132 appears to be fixed on the trunk.

Last night, I checked out the CVS sources for emacs, according to
instructions posted at http://savannah.gnu.org/cvs/?group=emacs.

This morning, I followed the directions in INSTALL.CVS to compile from
source.  The specific commands I used were

   ./configure --with-ns
   make bootstrap
   make install

According to (emacs-version) the version number of this emacs is
23.1.50.1.

In version 23.1.50.1, the tool bar icons appear correctly -- as color
icons, not black and gray silhouettes.  I will attach a screen shot,
produced by my earlier `Steps to Reproduce'.  This screen shot shows
the correct icon presentation.

Steve