WP Plugin: Solved Featured Image From URL not show image

This step by step:

1. Create file thumbnail.html in .../wp-content/plugins/featured-image-from-url/includes/html/, and PUT THIS CODE:
<a href="http://adf.ly/665625/<?php echo $url; ?>" target="_blank">
<img
	src="<?php echo $url; ?>" onError="this.src='/nocover.jpg';"
	alt="<?php echo $alt; ?>" >
</img></a>

2. Open file thumbnail.php in ..../wp-content/plugins/featured-image-from-url/includes/, and FIND THIS CODE:


line 46::

function fifu_get_html($url, $alt) {
	return sprintf('<!-- Featured Image From URL plugin --> <img src="%s" alt="%s"></img>', $url, $alt);
}

add_filter('the_content', 'fifu_add_to_content');

function fifu_add_to_content($content) {
	if (is_singular() && has_post_thumbnail() && get_option('fifu_content') == 'toggleon')
		return get_the_post_thumbnail() . $content;
	else
		return $content;
}

add_filter('wp_get_attachment_url', 'fifu_replace_attachment_url', 10, 2);

function fifu_replace_attachment_url($att_url, $att_id) {
	if (get_option('fifu_attachment_id') == $att_id) {
		if (is_admin())
			$att_url = '/wp-content/plugins/featured-image-from-url/admin/images/fifu-text.jpg';
		else {
			$url = get_post_meta(get_the_ID(), 'fifu_image_url', true);
			if ($url)
				$att_url = $url;
		}
	}
	return $att_url;
}

REPLACE WITH THIS CODE:

function fifu_get_html($url, $alt) {
	include 'html/thumbnail.html';
	return sprintf('<!-- Featured Image From URL plugin --> <img src="%s" alt="%s"></img>', $url, $alt);

}