Thx to @WhXcjm now this extension supports external icons and images.
you can use an image by adding link:http://your-image.png
into the admin settings
e.g.link:https://cdnjs.cloudflare.com/ajax/libs/twemoji/15.0.3/72x72/1f970.png
![](https://i.ibb.co/m0qS32T/1.png)
New Version: 1.0.0