How to load the header images before the content images?

I posted a similar question, but I believe this is the essence of what I am looking for! For some reason all of my content is loading before the header. I am using the Panorama theme. The index.php file is set up like this…

<?php get_header(); ?>
<div id=”content”>
<div id=”content-inner”>
<div id=”main”>….

I’m pretty sure that means the header is supposed to load before the content. But the images in the content are loading much much quicker than the header image, making my site look super-slow. Many of my posts are graphic-heavy, but I wish I could at least get the background, header, and sidebar images loaded before the content. From there I will use caching (currently disabled). I have spent lots of time trying to find a solution, so I would appreciate any advice. Thank you!