Not only can you embed GIFs into your content but you can make them your story image too!
https://giphy.com/ is a great resource to use to select already created GIFs or even make some of your own.
You can add a GIF the same way you would a regular story image in Content Manager > Story Icon and then clicking the purple plus button under Story Image. A box will pop up requesting a URL. If you are grabbing your GIF from giphy.com, select your preferred GIF> select 'Copy Link' > select 'GIF Link' and copy.
Paste the 'GIF Link' into the URL space and you're good to go!
You can also copy a link straight from Google or grab one already saved on your computer.