We use several methods to improve perceived download speeds. One of those methods is content prioritization. We prioritize the resources needed to present the page to visitors.
Above the Fold
Content that appears above the fold is always loaded first. The term above the fold comes from the days of printed newspapers when the most important stories were always presented on the top half of the page. Now that means the information displayed in the browser viewport when a page initially loads.
In most cases, your logo is displayed first to establish your brand. Next, we load menu information to allow visitors to begin navigating immediately if desired. Next, we load photos because that’s what we sell—our photography. And finally, we load everything else needed for page content.