Custom Header causing SSL issues (suffusion theme)

My site is secure except for my custom header image which shows as https://imagelocation instead of https://imagelocation

It’s hosted on a subdomain of my site, and when I provide the path to my image in https:// form it doesn’t load, but when I drop the “s” it loads perfectly.

Here is my site: https://donjuaninc.com

Here is the tutorial I followed to configure my subdomain: https://www.techtipsgeek.com/host-images-wordpress-blog-subdomain-better-speed/6897/ (I didn’t do the “update old posts”)

Thanks in advance,

Ryan