NOTE: You can also use animated gif icons, you can try giphy:
Here's a guide for using icons8
Start by visiting https://icons8.com/
Search for an icon and click it
Click "Embed HTML"
Copy the image URL in the src part of the snippet
Paste the copied link into the Image input in ProveSource.
Learn more about customizing the icon with icons8 URL formatting here: http://img.icons8.com/