According to a number of reports, Twitter is close to adding a photo-sharing feature similar to that provided by third-party services such as Twitpic and Yfrog. The addition seems like a natural for the information-sharing network — so obvious, in fact, that many have wondered why Twitter didn’t add the ability a long time ago. But while the new feature will almost certainly spark renewed concerns about Twitter bulldozing its third-party ecosystem, the big question is whether image-sharing can help the company figure out how to make money.