Images are rendered as links when using xhtml/1.0 or html/4.01 as the storage syntax

The following steps reproduce this bug:

• Create a new page and set its syntax to xhtml/1.0 or html/4.01 (if these syntaxes don't appear in the syntax combo box then you have to add them in xwiki.cfg)
• Edit this page with the Wiki editor and type:

  foo <img src="http://www.google.ro/intl/en_com/images/logo_plain.png" alt="bar" title="foo" /> bar
  

• Save and view. The result is:

  <p>foo <!--startwikilink:http://www.google.ro/intl/en_com/images/logo_plain.png-->
    <span class="wikiexternallink">
      <a href="http://www.google.ro/intl/en_com/images/logo_plain.png" title="foo" src="http://www.google.ro/intl/en_com/images/logo_plain.png" alt="bar">
        <span class="wikigeneratedlinkcontent">http://www.google.ro/intl/en_com/images/logo_plain.png</span>
      </a>
    </span><!--stopwikilink--> bar
  </p>