Increasing Table Sizes by x

[MoombaDS]

I'm currently designing a website layout in which I'm using a recurring background. The background piece merges perfectly with the header and footer of the page, but only when it prints it out in full size. Since the text content of the site is printed over this piece of background, it repeats as the page increases in size. However, this means that unless the table resizes by the exact height of the background, it no longer merges with the footer of the page.

Is there any way, using any form of scripting, to get the tables to increase by x increments only in height (142px to be precise) so that every time the table grows it will increase by 142px in order to allow the background to merge with the footer.

Thanks in advance.