Late October 2013 Twitter added a feature that automatically expands tweets that contains images or video. Remember that Twitter will (supposedly) makes its initial public offering this week. It's with no doubt a way to introduce ads or promoted tweet images and video to their users and future share holders.
This said, as Twitter user, I find it to remove a lot of information from my timeline when having tweets text replaced by any media content. With the following, we easily can understand that we can have two tweets where one image stands up in place.