Comment 4 for bug 1714446

Unfortunately there are implications to enabling https support on cdimages.ubuntu.com. Many people use zsync and the use of https would stop that from working, plus the site is owned and operated by Canonical, so it is really up to them if they want to do it or not.

Yes, the links do ideally need to be changed, but will take time to complete as it seems to be coming from the theme (this needs FTP access which I don't have)