The full changelog is right past the fold…
• enjoy a more beautiful design on iPhone with wider timelines in all parts of the app
• receive a notification when a friend has joined Twitter
• improvements and bug fixes for lists
In order to share a photo from your iPhone’s camera roll, is just hit the photo icon on the bottom right corner of the Tweet box. Another subtle improvement: the new Tweet composer now displays your avatar and username.
Not only does that give you a better sense of how your tweet will actually appear, it also makes tweeting from multiple accounts a lot easier as you can now select a desired account just by tapping on your avatar.
On Android, Twitter gained richer notifications in the Notifications Drawer. As you know, these rich notifications can be expanded by swiping to see more details.