Lazysizes filter for wordpress post thumbnail attachment

lazysizes

<?php
/**
 * Created by PhpStorm.
 * User: Madila
 * Date: 21/06/2016
 * Time: 11:58
 */

add_filter('wp_get_attachment_image_attributes', 'lazysizes_data_src', 3);

function lazysizes_data_src($attr) {
    if(array_key_exists('data-lazysizes', $attr) && $attr['data-lazysizes']) {
        $attr['class'] = $attr['class'].' lazyload';
        $attr['data-src'] = $attr['src'];
        $attr['src'] = 'data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7';
    }
    return $attr;
}

add_filter('post_thumbnail_html', 'intrinsic_ratio', 10, 4);
function intrinsic_ratio($html, $post_id, $post_image_id, $size)
{
	$full_size = wp_get_attachment_image_src($post_image_id, $size);
	if (strpos($html, 'data-intrinsic') > -1) {
		$ratio = ($full_size[2] / $full_size[1]) * 100;
		$html = '<picture class="img-intrinsic entry-thumbnail" style="padding-top:' . $ratio . '%">' . $html . '</picture>';
	}
	return $html;
}