diff --git a/functions/image.xml b/functions/image.xml
index 424adae8af..7da5ffc79f 100644
--- a/functions/image.xml
+++ b/functions/image.xml
@@ -1,5 +1,5 @@
 <?xml encoding="iso-8859-1"?>
-<!-- $Revision: 1.52 $ -->
+<!-- $Revision: 1.53 $ -->
 <reference id="ref.image">
  <title>Image functions</title>
  <titleabbrev>Image</titleabbrev>
@@ -394,7 +394,10 @@
     identifier representing the color composed of the given
     <acronym>RGB</acronym> components.  The <parameter>im</parameter>
     argument is the return from the <function>imagecreate</function>
-    function.  <function>ImageColorAllocate</function> must be called
+    function.  <parameter>Red</parameter>, <parameter>green</parameter> and
+    blue are the values of the red, green and blue component of the requested
+    color respectively.  These parameters are integers between 0 and 255.
+    <function>ImageColorAllocate</function> must be called
     to create each color that is to be used in the image represented
     by <parameter>im</parameter>.
     <informalexample>