From the Twitter Blog:
1. The first new feature offers a simple way to see what’s happening on Twitter in relation to you. Just click on the new tab with your @username, and you’ll be able to see which of your Tweets are Favorites, plus the latest Retweets (of your Tweets), Tweets directed to you, and your new Followers.
2. The other new feature is the Activity tab. It provides a rich new source of discovery by highlighting the latest Favorites, Retweets, and Follows from the people you follow on Twitter – all in one place. It’s easier than ever to explore Twitter, connect with people, and discover what’s happening around the world.
These new features are available on the Twitter.com site.
3. Roll Out Underway Allowing Users to Upload Images Directly to Twitter (via PFSK)
However, third party services will continue to be supported. A few months ago we learned that Twitter was partnering with Photobucket to create the direct upload feature. If you don’t have access to this feature today keep looking. It should be available to all users in the next few weeks.