Simple Wordpress snippet to get a post thumbnail url

thumb.php

<?php

if( !function_exists('get_thumb_url') )
{
    function get_thumb_url($size='thumbnail',$id=null)
    {
        $id = ( $id ?: get_post()->ID );

        $thumb = wp_get_attachment_image_src( get_post_thumbnail_id($id), $size );
        
        return $thumb['0'];
    }
}