Now there's Squoosh.
Squoosh is a web app from Google that will optimize image sizes to reduce page load time.
I would have thought that web image optimization has already jumped the shark what with 100+ Mbps home broadband but what do I know? I realize that not everyone has that bandwidth. My mother only has 10Mbps.
Squoosh runs all in the browser and after you load it the first time you can run it offline. Again, not sure WHY you'd need to do that but it does work.
Anyway, on to what it does.
I sent a 1.44MB jpeg to Squoosh and it optimized it to 521KB, a savings of 66%. There was no discernible difference in the image.