How can I select which tags should be stripped from the footer?
I assume you are talking about a custom block that you add in the footer region of the site. In that case, you need to include all the HTML tags used to create a map image, which are &lt;area&gt;, &lt;img&gt;, and &lt;map&gt;.

I have tried with a block contained the following HTML.

&lt;img src="http://www.w3schools.com/tags/planets.gif" width="145" height="126" alt="Planets" usemap="#planetmap"&gt;

&lt;map name="planetmap"&gt;
  &lt;area shape="rect" coords="0,0,82,126" href="http://www.w3schools.com/tags/sun.htm" alt="Sun"&gt;
  &lt;area shape="circle" coords="90,58,3" href="http://www.w3schools.com/tags/mercur.htm" alt="Mercury"&gt;
  &lt;area shape="circle" coords="124,58,8" href="http://www.w3schools.com/tags/venus.htm" alt="Venus"&gt;
&lt;/map&gt;


Once I enable those HTML tags for the Filtered HTML input format, the HTML added to the page for that block is the following.

&lt;div id="block-block-1" class="clear-block block block-block"&gt;


  &lt;div class="content"&gt;&lt;p&gt;&lt;img src="http://www.w3schools.com/tags/planets.gif" width="145" height="126" alt="Planets" usemap="#planetmap" /&gt;&lt;/p&gt;
&lt;p&gt;&lt;map name="planetmap"&gt;&lt;br /&gt;
  &lt;area shape="rect" coords="0,0,82,126" href="http://www.w3schools.com/tags/sun.htm" alt="Sun" /&gt;&lt;br /&gt;
  &lt;area shape="circle" coords="90,58,3" href="http://www.w3schools.com/tags/mercur.htm" alt="Mercury" /&gt;&lt;br /&gt;
  &lt;area shape="circle" coords="124,58,8" href="http://www.w3schools.com/tags/venus.htm" alt="Venus" /&gt;&lt;br /&gt;
&lt;/map&gt;&lt;/p&gt;
&lt;/div&gt;
&lt;/div&gt;


Keep in mind that, since the function Drupal used to filter out HTML tags is filter_xss(), the HTML you pass to the Filtered HTML input format is altered to:


Remove characters and constructs that can trick browsers
Make sure all HTML entities are well-formed
Make sure all HTML tags and attributes are well-formed
Make sure no HTML tags contain URLs with a disallowed protocol (e.g. javascript:)


Then, also _filter_xss_attributes() is called; that means also tag attributes are filtered.