how to control size of photot in reademe code example

Example 1: github screenshots resize

![test image size]<img src="https://fullpath/assets/yourgif.gif" width="400" height="790">

Example 2: change size of image in github readme

<a href="url"><img src="http://url.to/image.png" align="left" height="48" width="48" ></a>