[tgv]

Some of my (non-programming) colleagues don't seem to be able to wrap their head around image size. And someone who taught courses to communication/marketing students told me, it took 2 hours to explain resolution and all that to them, and then half even didn't get it. Yeah, I can hear you: "something that easy? must have been a bad teacher," but the concepts are rather weird for non-techies. So those people become responsible for updating the website content, and upload whatever the graphical artists show them. And designers like to zoom in, a lot, so often that's a 20MB png, where a 200kB jpeg would suffice.