If you have any control over that web page you need to get those over-sized PNGs resized and re-encoded to jpgs. They are 2MB each, they could be about 100KB a

If you have any control over that web page you need to get those over-sized PNGs resized and re-encoded to jpgs. They are 2MB each, they could be about 100KB and do just as good a job at being scaled-down thumbnails. You are burning bandwidth - 8MB just to load the page.