It's easy. Just open up an account on Photobucket. Then Upload pictures from your computer to your photobucket account. Open Advrider in one tab and photobucket in the other so you can jump back and forth easier. Then go to your albums, move your cursor over the picture you want, a drop down menu will appear. Click on the one little box next to the IMG code, it will say copying. Then go to back to the reply to thread screen on Advrider, right click and paste. it will show up with IMG in  and then the Photobucket address of the picture then IMG in  at the end of it.
That's it easy.