<?php
 
$conteudonoticia = '[caption id="attachment_42478" align="alignleft" width="640"] <img class="wp-image-42478 size-full" src="http://paginalocal/wp-content/uploads/2016/12/20140815_174009.jpg" alt="20140815_174009" width="640" height="480" />Objetivo com a antecipação é garantir comodidade e tranquilidade aos servidores para as festas de final de ano[/caption]';
 
preg_match_all('#\bhttps?://[^,\s()<>]+(?:\([\w\d]+\)|([^,[:punct:]\s]|/))#', $conteudonoticia, $match);
 
 
 
$url = (implode(':', $match[0]));
 
echo $url;

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