I was having headaches with tables, so I drop a jpeg that I made and sliced in photoshop into dreamweaver and traced it which creates div tags. I uploaded it and everything shift to the left again.
I wasn't able to make tables since it seems to give me that 1 pixel gap between the picture and the table...
You can surround your content with a div that is set with the specific width of your page content and then assign a margin of left auto and right auto:
margin: 0 auto 0 auto; /* Sets the margin properties for an element using shorthand notation (top, right, bottom, left) auto right and left will centre it in the browser */