you have to upload it to a online storage or photo website....like image shack, picasa, or flickr.
Then use the Img tag in the ^above^ formatting bar, and paste in the image url.
{img}https://lh5.googleusercontent.com/-j0gscAERKAw/T-kfLBEDH1I/AAAAAAAAS2o/tVE7Iyg40vE/s1024/Draper%2520and%2520Baker.jpg{/img} <---looks like this....but has the right formatting.
so it ends up like this.