Load header image from (fix #104)

header.php

@@ -44,7 +44,11 @@
 	<a class="skip-link screen-reader-text" href="#content"><?php esc_html_e( 'Skip to content', 'pressbooks-aldine' ); ?></a>
 	<header class="header" role="banner" style="background-image: url(<?php
 	if ( is_front_page() ) {
+		if ( has_header_image() ) {
 			echo( get_header_image() );
+		} else {
+			echo get_template_directory_uri() . '/dist/images/header.jpg';
+		}
 	} else {
 		echo get_template_directory_uri() . '/dist/images/catalog-header.jpg';
 	} ?>);">

inc/actions/namespace.php

@@ -63,7 +63,7 @@ function setup() {
 
 	// Set up the WordPress core custom header feature.
 	add_theme_support( 'custom-header', [
-		'default-image' => $assets->getPath( 'images/header.jpg' ),
+		'default-image' => get_template_directory_uri() . '/dist/images/header.jpg',
 		'width' => 1920,
 		'height' => 884,
 		'default-text-color' => '#000',