1.获取magento当前浏览器的url

$currentUrl = $this->helper('core/url')->getCurrentUrl();

2.获取magento当前域名

$this->getUrl();

对url判断来显示不同的图片

<?php if(strpos($currentUrl,'promocatalog')):?>
<img src="<?php echo $this->getSkinUrl('images/home/top_bottom/sefenlei.png');?>"/>
<div>分类</div>
<?php else:?>
<img src="<?php echo $this->getSkinUrl('images/home/top_bottom/file_2.png');?>"/>
<div>分类</div>
<?php endif;?>