Index: source
===================================================================
--- source	(revision 2942)
+++ source	(revision 2943)
@@ -19028,6 +19028,10 @@
   views, then the <code title="attr-img-alt">alt</code> attribute must
   be the empty string.</p>
 
+  <p>In such cases, the <code title="attr-dim-width">width</code> and
+  <code title="attr-dim-height">height</code> attributes should both
+  be set to zero.</p>
+
 
 
   <h6>An image in an e-mail or document intended for a specific person who is known to be able to view images</h6>
@@ -27876,7 +27880,7 @@
   respectively, relative to the nominal direction of the output
   medium), in CSS pixels. The attributes, if specified, must have
   values that are <span title="valid non-negative integer">valid
-  non-negative integers</span> greater than zero.</p>
+  non-negative integers</span>.</p>
 
   <p>The specified dimensions given may differ from the dimensions
   specified in the resource itself, since the resource may have a
@@ -27895,6 +27899,8 @@
              <var title="">specified width</var> / <var title="">target ratio</var> &le;
              <var title="">specified height</var> + 0.5</span></li>
 
+   <li><span title=""><var title="">specified height</var> = <var title="">specified width</var> = 0</span></li>
+
   </ul>
 
   <p>The <var title="">target ratio</var> is the ratio of the
@@ -27907,8 +27913,12 @@
   <p>The two attributes must be omitted if the resource in question
   does not have both an intrinsic width and an intrinsic height.</p>
 
-  <p class="note">Basically, the dimension attributes can't be used to
-  stretch the image.</p>
+  <p>If the two attributes are both zero, it indicates that the
+  element is not intended for the user (e.g. it might be a part of a
+  service to count page views).</p>
+
+  <p class="note">The dimension attributes are not intended to be used
+  to stretch the image.</p>
 
   <div class="impl">