As imageshack likes to not work sometimes and lose pictures other times, I'd suggest using either http://www.imgur.com or http://www.use.com But whichever you decide to use.. once you've uploaded your picture and know the web address directly to the image itself, here at TSD just click the little icon that looks like a tree surrounded by a white border. A box will pop up for you to paste the web address to the image.
hope that helps what jody said....I use photobucket to upload all my pics...its free, organized and never fails me!