A little behind the times, Flickr just added Twitter support. I am waiting for the day I can use it with Tweetie. I’ve got lots of photos stored on my Flickr account. And I have used it since before Yahoo! bought the service. I have so many photos there that I paid for the service.
Right now I am using TwitPic service because with Tweetie you have a choice of either TwitPic or yfrog. While I’d love to keep all my photos together in the same location, convince wins. It is more convenient to snap a photo using Tweetie & upload directly to TwitPic than to take a photo, copy into an email then type the Twitter into the subject line & hope it is less than 160 characters.