We would need some modification from Tom’s code.
Try this snippet:
add_action( 'generate_inside_mobile_header','lh_mobile_logos' );
function lh_mobile_logos() {
?>
<div class="site-logo mobile-header-logo">
<img src="URL TO MOBILE HEADER LOGO" alt="" />
</div>
<div class="site-logo mobile-header-logo sticky-only">
<img src="URL TO STICKY MOBILE HEADER LOGO" alt="" />
</div>
<?php
}
And this CSS:
.mobile-header-logo.sticky-only {
display: none;
}
.navigation-stick .mobile-header-logo.sticky-only {
display: block;
}
.navigation-stick .mobile-header-logo:not(.sticky-only) {
display: none;
}