I’ve tried this out as an example by using the meta slider plugin. Assuming you have a child theme, you can then create your own version of header.php (start by copying the illdy header.php). Then you can add the shortcode metaslider gives you eg: echo do_shortcode(“[metaslider id=109]” into the bottom of your header.php.
Then a simple way to completely hide the single image that illdy loads would be to add some css like this to your child themes style.css file:
.site-header {
display: none;
}