It's your web browser that determines how emojis are rendered.
The same emoticon, or emoji or whatever it is, in that first post, viewed on different browsers/platforms... Note: the differing sizes are because I was hasty doing the screen snips.
Computer 1:
Windows 10
Google Chrome
Internet Explorer 11
Firefox 54
Computer 2:
Debian Linux 8 (Jessie)
Firefox 45 ESR
Konqueror web browser (KDE 4.14.2)
Smart phone:
Android Marshmallow
Google Chrome