Media assets' weight is one of the biggest enemies of mobile devices. It says that roughly 60 to 70 percent of a site's weight is consumed by images, and this has been growing rapidly due to high-density displays.
When we build responsive websites, we remove the width and height attribute of an image, and we set the max-width 100 percent using CSS. By doing this, we make this image responsive and whatever the screen size is, the image will be resized for that screen.
Of course, this strategy requires developers to use images that are at least as large as the largest screen size at which they'll be displayed; if an image is expected as part of a layout, that could be anywhere from 320 px to 1,600 px, and the developer still requires to serve an image with an inherent width of at least 1,600 px. That's a tremendous amount of drained bandwidth and processing power for a mobile device, with no obvious advantage to the user. This bandwidth cost is increased by...