Check in indexed2rgb.sh script,

...so the imagemagick docs don't need to be read again for this task

utils/indexed2rgb.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+#
+#  Script to convert PNGs from indexed to RGB mode.
+#
+#  Run-time requirements: ImageMagick
+#
+
+while [ "${1}" != "" ]; do
+    # Rather useless until we start accepting options, but whatever.
+    filelist="${filelist} ${1}"
+    shift
+done
+
+if test -z "$filelist"; then
+    filelist=`find -iname "*.png"`
+fi
+
+number=`echo $filelist|wc -w`
+
+echo "Converting $number files to RGB mode..."
+
+for f in $filelist
+do
+    convert -define png:color-type=TrueColor $f $f.new
+    mv -f $f.new $f
+done
+
+echo "Done. Now would be a good time to run optipng"
+