When posting to Twitter via the www.twitter.com web site there is not a function to upload pictures directly from the post window. The easiest way to associate an image is to use the third party service called TwitPic. If you consistently use the same service then you can also see a complete history of every image you have uploaded to your twitter posts by visiting the URL associated with your account. The other benefit of using Twitpic is the fact that if you have a Twitter account then you already have a Twitpic account that uses the same username and password. Follow the directions below to post an image when posting to your Twitter account using the web interface at www.twitter.com.