1、随着屏幕的宽度,加载不同图片;
<picture>
<source srcset="pic1.png" media="(max-width: 600px)" />
<source srcset="pic2.png" media="(max-width: 800px)" />
<img srcset="pic3.png" alt="pic" />
</picture>
<picture>
<source srcset="pic1.png" media="(max-width: 600px)" />
<source srcset="pic2.png" media="(max-width: 800px)" />
<img srcset="pic3.png" alt="pic" />
</picture>