Upgrade to the latest version of SB, select all items and revise. The footer will update to HTTPS…
Per answer john gave in forum.
I just tried that (updraded to 3.00.208) and the image address is still https://www.sixbitsoftware.com/images/tagline.jpg with the link disabled. I got that URL from Copy Image Address. If you Open Image in a New Tab it’s HTTPS so maybe there’s a redirect? I know the revision went through because I made other changes as well.
What’s weird is that View Page Source doesn’t show anything for the SixBit link or much of my description.