Jack Dorsey, writing on the Twitter Blog:

Millions of people share photos on Twitter every day. We’re going to make that easier than ever. Over the next several weeks, we’ll be releasing a feature to upload a photo and attach it to your Tweet right from Twitter.com. And of course, you’ll soon be able to easily do this from all of our official mobile apps. A special thanks to our partner Photobucket for hosting these photos behind the scenes. Services like yFrog and Twitpic are in trouble. Other services like MLKSHK who provide more value that just a dump for photos might be okay though.