You can now add four photos to a single tweet and for the first time, you can tag up to 10 friends in a Twitter photo, without taking away from your 140-character count.
The photos you add will appear as a four-part collage in your timeline.
Twitter Is adding more and more features from both Google+ and Facebook. This new photo sharing feature is pretty cool though, but it only works from the iPhone for now. They will add Twitter.com and Android support later.