Disable search media URL and Attachments

Copy and paste the following code to the functions.php of your current theme.

<?php

//disable media url/attachment url
add_action(
	'template_redirect',
	function () {
		global $post;
		if ( ! is_attachment() || ! isset( $post->post_parent ) || ! is_numeric( $post->post_parent ) ) {
			return;
		}

		// Does the attachment have a parent post?
		// If the post is trashed, fallback to redirect to homepage.
		if ( 0 !== $post->post_parent && 'trash' !== get_post_status( $post->post_parent ) ) {
			// Redirect to the attachment parent.
			wp_safe_redirect( get_permalink( $post->post_parent ), 301 );
		} else {
			// For attachment without a parent redirect to homepage.
			wp_safe_redirect( get_bloginfo( 'wpurl' ), 302 );
		}
		exit;
	},
	1
);