Get the best version of youtube cover image without using the API

youtube-cover-art.php

<?php

function url_exists( $url ) {
	$headers = get_headers($url);
	return stripos( $headers[0], "200 OK" ) ? true : false;
}

function get_youtube_id( $url ) {
	$youtubeid = explode('v=', $url);
	$youtubeid = explode('&', $youtubeid[1]);
	$youtubeid = $youtubeid[0];
	return $youtubeid;
}

function get_youtube_thumb( $id ) {
	if ( url_exists( 'https://i.ytimg.com/vi_webp/' .$id . '/maxresdefault.webp' ) ) {
		$image = 'https://i.ytimg.com/vi_webp/' .$id . '/maxresdefault.webp';
	}
	elseif ( url_exists( 'https://i.ytimg.com/vi_webp/' .$id . '/mqdefault.webp' ) ) {
		$image = 'https://i.ytimg.com/vi_webp/' .$id . '/mqdefault.webp';
	}
	elseif ( url_exists( 'https://i.ytimg.com/vi/' .$id . '/maxresdefault.jpg' ) ) {
		$image = 'https://i.ytimg.com/vi/' .$id . '/maxresdefault.jpg';
	}
	elseif ( url_exists( 'https://i.ytimg.com/vi/' .$id . '/mqdefault.jpg' ) ) {
		$image = 'https://i.ytimg.com/vi/' .$id . '/mqdefault.jpg';
	}
	else {
		$image = false;
	}
	return $image;
}

// Example:

$youtube_url = 'https://www.youtube.com/watch?v=ferZnZ0_rSM';
$id = get_youtube_id( $youtube_url );
$thumb = get_youtube_thumb( $id );
echo '<img src="' . $thumb . '" alt="">';