The swipe has been a long time coming and starts to eat away at third party apps.
For the first time, you can share and view photos via direct message (DM) on your mobile phone. We’ve also introduced a new tab in the navigation bar that makes it easy to access DMs –– they’re just one tap away from wherever you are on Twitter. You can also view photos in DMs on twitter.com.Twitter Mobile Apps Get Photos In DMs and Swipe Between Timelines [blog.twitter.com]
Now you can swipe from your Home timeline to the Discover timeline to find trends, popular Tweets and new accounts tailored for you, and then swipe to your Activity timeline to see Tweets and accounts that are popular among people you follow.