If you're wondering whether it's worth your while to use a responsive images solution on your site, Sizer Soze can help you out. Just enter the URL, experiment with a few breakpoints and it will tell you how much data you can save.
If you do decide that you want to go responsive, it points you in the direction of this handy guide from Chris Coyier, which explores the various techniques that you can use to serve up the right image for the situation at hand.
