adding special treat for people actually using the branding guidelines by providing them an emoji size image file

Author: rouzbeh84

assets/icon-square-small-slack.png

@@ -54,6 +54,10 @@ Square-sized icon for smaller areas (like favicons):
 
 [svg](https://github.com/webpack/media/blob/master/logo/icon-square-small.svg) | [png](https://github.com/webpack/media/blob/master/logo/icon-square-small.png) | [jpg](https://github.com/webpack/media/blob/master/logo/icon-square-small.jpg)
 
+T> For those of you following our guidelines and have gotten this far, we've made a special smaller size image used especially for custom emoji (like in a slack or gitter channel ;))
+
+<img src="./assets/icon-square-small-slack.png" width="50" alt="icon square small example">
+
 ## Font
 
 We use the beautiful [Geomanist Medium](http://geomanist.com/) font from the extremely talented folks at the [Atipo Foundry](http://atipofoundry.com/) who provide the entire font family at a 'pay what you want' model.