how to add image in md code example

Example 1: how to insert an image in markdown

![image info](./pictures/image.png)

Example 2: markdown embed image

![Image of Yaktocat](https://octodex.github.com/images/yaktocat.png)

Example 3: how to add image in readme.md

![alt text](http://url/to/img.png)

Example 4: how to add image in readme.md

![alt text](https://github.com/[username]/[reponame]/blob/[branch]/image.jpg?raw=true)