Django sorl-thumbnail无法识别图像文件

Question

我在django模板中使用for循环运行了几个事件，我想阻止那些没有图像显示但是我收到此错误

IOError at /buy-sell/category/housing/page/19

cannot identify image file

...

{% if e.picture.url %}
  {% thumbnail e.picture "300x600" as thumb %}
     <img src="{{ thumb.url }}" alt="{{ e.title }}" />
  {% endthumbnail %}
{% endif %}