How to update source file information

I am getting an insecure site notice from Google. I ran a program called WhyNoPadlock and it identified 35 .jpg files that are being linked from an http:// site. I went thru and edited all of the links with a .html editor and changed them to https://. This didn’t work. The links keep reverting back to http://.

What file(s) in WP have this .html information? Where/how can I update them so the site will be secure according to Google?

The page I need help with: [log in to see the link]