Imagine if you could post pictures in the chat. Both mobiles and PCs would be able to send a picture on the chat. Furthermore, mobile users could take a selfie that moment. You could test this feature, so the mods and the streamer can post pics, if everything goes okay, subs and viewers should be able to post pics too (But a moderator or the streamer should verify it first).
This feature will bring people closer. It wont be the faceless chat we all know.. It brings the reality of the gameworld to twitch.