markdown调整图片尺寸

使用百分比描述尺寸

<img src="https://img2018.cnblogs.com/blog/1122471/201902/1122471-20190222185756735-1641099963.png" width="60%">

使用宽度描述尺寸

<img src="https://img2018.cnblogs.com/blog/1122471/201902/1122471-20190222185756735-1641099963.png" width="600">

没有尺寸描述

<img src="https://img2018.cnblogs.com/blog/1122471/201902/1122471-20190222185756735-1641099963.png">

或

![](https://img2018.cnblogs.com/blog/1122471/201902/1122471-20190222185756735-1641099963.png)