Twitter's Jaikumar Ramanathan said one of the features is improved photo sharing.
"Photo streams for profiles display the images people have shared on Twitter," he wrote.
"Whenever you see a photo stream, swipe left or right through the thumbnails or tap to view photos in fullscreen mode. Android users can also get closer to photos with pinch-to-zoom."
Twitter, which allows its members to post brief comments, links or pictures, claims to have more than 140 million active users, with the largest number being in the United States.
A recent survey found one in seven Americans who go online use Twitter and eight% do so every day.