Creating a fluid design that will fit any window resolution can be difficult unless the page doesn't have much content. It will look very squashed up in a small width window like 320px on a hand-held device or very spaced out in a 1920px window. The alternative is to use fixed widths, but using min-width and max-width for the page container which limits the expanding and contracting. Divs inside can have no width and should create their own width for text.
If you want to make a totally fluid page, code all element widths (divs, ul tags, forms, tables, etc.), side margins, side padding and images in % widths totalling 100%. Images coded
Code:
<img style="width: 35%;" src="image.jpg" alt="description" />
without a height will have the height adjust in proportion to the width.
Side borders cannot be sized in % so if you have these, make the total of other items 97% or 98% to allow for the side borders in px.
In your case remember that the hot spots will need to be fluid as well to remain in the correct place on a background that is stretching.
When you code a fluid width page, start without any heights as elements will have to expand vertically.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.