While it's usually the elements in the foreground, such as navigation elements, images, or content, that catch a user's eye, the background is something not to be pushed into the background. Given that there are so many variables across multiple platform and browsers, there are a few considerations to make to ensure that what you see is what the user will get. The Web is an elastic medium, and although one can try to code specific precise pixel placement, there is a certain amount of chaos theory that will enter into the mix. Although table coding allows for a mostly reliable arrangement of the foreground elements, there is no real easy way to specify a precise alignment of the table with the background.
Different browsers have a different offset of the first element from the frame border.
This can vary up to 10 pixels. It's possible to work around this with frames, but it introduces an entirely new can of worms. It's rather like fake frames, but in the end it's an elegant solution. If the stripe is unadorned with additional pattern, the image need only be a single pixel in height. It's important to remember that as it repeats down the page, given the opportunity, it will repeat at the right as well.