Enabled SSL, See lock if I remove header image. Want the lock to show...

Hello.

I have enabled SSL but couldn't get the lock to display on our website. I ran a test and saw that our header image was not valid to be secured and was the only thing limiting it. The logo is displayed from our theme's control panel. When I remove the logo, the lock appears on my website which is what we want.

However, we also need our logo. Any way to get this to pass?

http://cityofhanahan.com

Thanks in advance,
David