You need the pics to be hosted on a photo album site such as
http://www.photobucket.com (Free) and once you signed up, upload your pictures and click the picture you want to view n right click with ur mouse and click PROPERTIES and Then Find the URL Address and copy it.., (Paste the url to the following...)then go on here and find the (PIC) button while your replying to a thread. or use [img*]url addy[*/img] (REMOVE THE STARS, I placed it to show the code)and u should be all set.