Then, you load pictures from your computer to your account on one of these sites.
Then, you obtain the URL from the picture you want to post.
then, you copy that URL and come back to the dis and select the icon in the message menu title bar for new messages that looks like a postcard with a mountain and a sunset (or postage stamp depending on your view)
Paster you URL into the pop-up window and voila, presto magico your picture will be posted for all to see.