1：背景图片管理
<body background="E:/PyCharm 2020.1.1/project/MySite/static/image/short_detect/index_image.jpg">
...
<body>
2：body图片管理
{% load static %}
<img src="{% static "E:/PyCharm 2020.1.1/project/MySite/static/image/short_detect/index_image.jpg" %}" alt="index image"/>
