I think that kind of drives the point home. Maybe it's my display or my vision, but I still can't tell a difference between the "Before" and "After" pictures. That's very impressive to me, looking at the compression ratios.

I discarded the idea of using a sliding divider because it cannot switch images fast enough to notice tiny compression artifacts, if any.

But thanks for your feedback. I have a couple of ideas how to make it more clear.