$url_to_image = "http://anime-source.com/html/images/ichigo/chapter001/Ichigo-01-01.jpg";
$url_to_image = "http://anime-source.com/html/images/ichigo/chapter001/Ichigo-01-04.jpg";
$xComics = New xComics();
$url_to_image = $xComics->build_image_url('1', 'be');
if(!$xComics->exists_image($url_to_image))
{
unset($url_to_image);
$xComics->back_in_time(4, '1', 'be');
}