If you want to attach a picture, when you are posting there is a button at the bottom. (Attach File) click on it locate the picture on your computer and attach it. If you want the picture to show up like the one 2 posts above, the picture needs to be on some sort of webspace. Either yours or w/e you have to link the image from another net location. To do that you click the (IMG) button up top when you are posting and enter the destination of where the pic is located on the web.
hope this helps you
Greg.