There is a much higher level of Twitter integration in Mountain Lion. For instance, you can tweet right from the Notification Center or share links from Safari with just a few clicks. Another cool feature that Apple has built into OS X is the ability to switch your Twitter profile picture right from Photo Booth.
To do this, first go to System Preferences > Mail, Contacts & Calendars to set up your Twitter account. After your Twitter account is configured, go through the available options for it in System Preferences > Notifications to choose how you want to be informed when you get mentions or direct messages.
Now for the profile picture. Open Photo Booth and take a picture of yourself, select the photo, and click the small arrow on the right side of the window and choose Change Twitter Profile Picture, as seen in the photo at the top of this post. When you hear the little bird sound, you’re picture has been changed.
At the same time, you can also check out some of the other Mountain Lion options, like sharing to Flickr or sending an image through AirDrop.