第一步:打开top10.lib
在下面这行代码下:
<!-- {foreach name=top_goods from=$top_goods item=goods}-->
添加:
<!-- {if $smarty.foreach.top_goods.iteration == 1} -->
    <a href="{$goods.url}"><img src="{$goods.goods_thumb}" alt="{$goods.goods_name}" /></a>
    <!-- {/if} -->

第二步:打开lib_goods.php
找到:
* 调用当前分类的销售排行榜
在其下面这段代码中找到：(大概是116行)
   $sql = 'SELECT g.goods_id, g.goods_name, g.goods_img, SUM(og.goods_number) as goods_number ' .
修改为:
   $sql = 'SELECT g.goods_id, g.goods_name, g.goods_thumb,g.goods_img, SUM(og.goods_number) as goods_number ' .
即增加了一个读取缩略图的字段：g.goods_thumb

再找到:
$arr[$i]['goods_img'] = get_image_path($arr[$i]['goods_id'], $arr[$i]['goods_img']);
在下面添加这行:
$arr[$i]['goods_thumb'] = get_image_path($arr[$i]['goods_id'], $arr[$i]['goods_thumb']);

OK 搞定