In order to compete with the popularity of Snapchat, Twitter recently announced on its blog that it created a way to "Illustrate your Tweets," though this feature is currently only for Android users.
The app is "optimized specifically for Android tablets" and allows users to doodle on photos and share them. Twitter released a short Vine demonstrating the capabilities of this app by illustrating the Golden Gate Bridge, which also shows that drawings can begin on a blank slate.
Hopefully this app will not just be exclusive to Android tablet users in the future, since the prospect of being able to illustrate your tweets will likely create a surge in popularity across the social media platform. Since Twitter is largely text-based, this app could help to introduce a lot more visuals to the site.