Showing gifs need two things
1- Use this syntax as in these examples
![Alt Text](https://media.giphy.com/media/vFKqnCdLPNOKc/giphy.gif)
Yields:
2- The image url must end with gif
3- For posterity: if the .gif link above ever goes bad, you will not see the image and instead see the alt-text and URL, like this:
4- for resizing the gif you can use this syntax as in this Github tutorial link
<img src="https://media.giphy.com/media/vFKqnCdLPNOKc/giphy.gif" width="40" height="40" />
Yields: