If you have noticed, one of the way that highly-trafficked site save bandwidths is to use a lazy load plugin. What this lazy load plugin does is to load the images only when they become visible on the screen. Any images below the visible screen will not be displayed. This is also known as on-demand loading.
In WordPress, there are several lazy load plugins that you can use. One of my favorite is the jQuery Image Lazy Load plugin, simply because it just works the moment you activate it. No configuration is required.