title: add an image field to wordpress category
body: <p>i am trying to add an image field to the <code>wp_term</code> table in the <code>database</code>, I'll call it <code>icon</code>.</p>
  
  <p>I want that filed to contain a <code>URL</code> to an image that will be the thumb for the category.
  I have already added the field to the <code>DB</code> and I have also inserted it into the code in the admin panel :</p>
  
  <pre><code>&lt;?php if ( is_taxonomy_hierarchical($taxonomy) ) : ?&gt;
      &lt;tr class="form-field"&gt;
          &lt;th scope="row" valign="top"&gt;&lt;label for="icon"&gt;&lt;?php _ex(' Icon', 'Taxonomy Icon'); ?&gt;&lt;/label&gt;&lt;/th&gt;
          &lt;td&gt;&lt;input name="icon" id="icon" type="text" value="&lt;?php if ( isset( $tag-&gt;icon ) ) echo esc_attr($tag-&gt;icon); ?&gt;" size="40" /&gt;
          &lt;p class="description"&gt;&lt;?php _e('The &amp;#8220;icon&amp;#8221; is the URL to the category icon. if it is an uploaded image it will be http://'.$_SERVER['SERVER_NAME'].'/wp-content/uploads/{your_file.name}.'); ?&gt;&lt;/p&gt;&lt;/td&gt;
      &lt;/tr&gt;
  &lt;?php endif; // is_taxonomy_hierarchical() ?&gt;
  </code></pre>
  
  <p>the code shows the content from the <code>database</code> if it is preset but doesnt update it.</p>
  
  <p>what/where do i need to add so that it will also update the <code>DB</code> <code>icon</code> field?</p>
  
  <p>thank you.</p>