Snore

simple question but its bothering me and i dont know why its happening... Alright i am creating a personal website used photoshop and sliced the image up the way i wanted it. But now when i go in to dreamweaver and try to turn one of my slices that contains something i want to put a url to eveything shifts sizes and spreads out a little bit and throws off my entire design... any suggestions as to what i am not doing right?

sorry if it sounds confusing