Need to show "HOME" link only on sub album pages

on the sub album pages I need a link back to the main album, and it should be hidden on the main album page

I tried this:
{if ($smarty.get.g2_itemId)}
<a href="main.php">HOME</a>
{/if}

but the smarty conditional doesn't work, I wish I could just use plain php there, at least I know how that works.

Any other ideas?

Here is code for Gallery 2.3 (the link above is for 2.2). In this example, I don't want the logo to appear on any page except the root album:

Edit file "/themes/carbon/theme.inc" for standard theme "carbon":

/**
     * @see GalleryTheme::showAlbumPage
     */
    function showAlbumPage(&$template, $item, $params, $childIds) {
	$ret = $this->loadCommonTemplateData(
	    $template, $item, $params,
	    array('owner', 'viewCount', 'childCount', 'descendentCount', 'parents',
		  'systemLinks', 'itemLinks', 'itemSummaries', 'permissions',
		  'thumbnails', 'pageNavigator', 'jumpRange'),
	     $childIds);
	if ($ret) {
	    return array($ret, null);
	}

	/* Add in our extra stuff */
	$theme =& $template->getVariableByReference('theme');
	$theme['columnWidthPct'] = floor(100 / $params['columns']);

	/* Check for JavaScript warning flag */
	if (GalleryUtilities::getRequestVariables('jsWarning') != null) {
	    $template->setVariable('jsWarning', true);
	}

          
    	  /* fotonut comment :Add check for being in main album.  ref: http://codex.gallery2.org/Gallery2:How_to_add_custom_stuff_on_main_root_page */
    	  /* get the rootId */
            list ($ret, $rootId) = GalleryCoreApi::getPluginParameter('module', 'core', 'id.rootAlbum');
            if ($ret) {
                return array(null, 'theme.tpl');
            }
            if ($item->getId() == $rootId) {
                $isItRoot = true;
            }
            $template->setVariable('isItRoot', $isItRoot);
            /* end of add by fotonut */


	/* Add our header and styles */
	return array(null, 'theme.tpl');

    }

    /**
     * @see GalleryTheme::showPhotoPage
     */
    function showPhotoPage(&$template, $item, $params) {
	$dataTypes = array('owner', 'parents', 'systemLinks', 'itemLinks', 'permissions',
			   'itemLinksDetailed', 'itemNavigator', 'imageViews');
	if (!empty($params['showMicroThumbs'])) {
	    $dataTypes[] = 'navThumbnails';
	}
	$ret = $this->loadCommonTemplateData($template, $item, $params, $dataTypes);
	if ($ret) {
	    return array($ret, null);
	}

	/* Check for JavaScript warning flag */
	if (GalleryUtilities::getRequestVariables('jsWarning') != null) {
	    $template->setVariable('jsWarning', true);
	}

	return array(null, 'theme.tpl');
    }

Edit file "/themes/carbon/templates/local/theme.tpl" for standard theme "carbon":

<div {g->mainDivAttributes}>
      {*
       * Some module views (eg slideshow) want the full screen.  So for those, we don't draw
       * a header, footer, navbar, etc.  Those views are responsible for drawing everything.
       *}
      {if $theme.useFullScreen}
	{include file="gallery:`$theme.moduleTemplate`" l10Domain=$theme.moduleL10Domain}
      {elseif $theme.pageType == 'progressbar'}
	<div id="gsHeader">
          {if !empty($theme.params.logoImageLocation)}
	  <img src="{g->url href=$theme.params.logoImageLocation}" alt=""/>
          {else}
	  <img src="{g->url href="images/galleryLogo_sm.gif"}" width="107" height="48" alt=""/>
          {/if}
	</div>
	{g->theme include="progressbar.tpl"}
      {else}
      <div id="gsHeader">
	<table width="100%" cellspacing="0" cellpadding="0">
	  <tr>
	    <td align="left" valign="top" width="50%">
	      <a href="{g->url}">
	          {*
                   * fotonut: Only show the logo if we are on the root.  We added a flag isItRoot to the associated Theme.inc
                   *
                   *}
                {if $isItRoot}
        		{if !empty($theme.params.logoImageLocation)}
        		<img src="{g->url href=$theme.params.logoImageLocation}" alt=""/>
        		{else}
        		<img src="{g->url href="images/galleryLogo_sm.gif"}" width="107" height="48" alt=""/>
        		{/if}
		{/if}
              </a>
	    </td>
	    <td align="right" valign="top">
	      {g->theme include="ads.tpl"}
	    </td>
	  </tr>
	</table>
      </div>