Previously I had asked about resizing the header image and understand that is not possible, it can only be cropped. But I have another question, since what I want to do is to have small 150px x 200px images in each of the two sidebars that are always present regardless of the browser width, and only have the center image be cropped based upon browser size. Is it possible to make the header image a collection of 3 images, one left aligned, one centered, and one right aligned and have the center one cropped based upon the width of the center section?

Thanks in advance for your help.

Technically, yes, but you need to create this from scratch or heavily modify the existing code