I think that we may have Emoticons, and maybe stickers, added to the steemit platform in the future. For now, just add images like you did in your post. I wrote about this same thing, 3 weeks ago, here: https://steemit.com/steemit/@kenny-crane/emojis-on-steemit-how-do-we-all-feel-about-them-and-how-to-add-them

Best wishes!