Header image isn’t changing…

I’m changing the header image of a theme for a client and have the image renamed EXACTLY as it was (header.jpg) and uploaded to the webspace via Cyberduck AND Filezilla to but the image will not refresh in my browser. I’ve emptied the cache and refreshed and the original blue image is still appearing. It should be a black header. I’ve done this a million times and can’t figure out where I’m going wrong with this one!

The URL is https://www.madhatterdesigncompany.com/wptest

I’m not sure what else is needed to help me resolve this, so let me know if additional details are needed.

Thanks!