I've uploaded the Misty Lake v1.1 theme to my self-hosted WordPress site, and can apply the theme to my blog, but do not have an option to customize the header image using the wp_admin panel. When I go to "Customize" and pull down the Header Image dropdown that shows the default image, the panel just shows the default image under a tab of "Default" and a link to "Remove Image" which will remove the image entirely. Why is there no "Upload New" option, as there is with the Background Image?
Do I need to create a child theme in order to customize the header? I've not done this before, so if anyone has any tips/tricks on how best to do this for Misty Lake, I'd greatly appreciate them to avoid me having to dig unnecessarily.