<?php
$image = YOURIMAGETAG; //like: <img src="http://domain/sites/default/files/imagecache/Home_Feature/flexpromo/images/home-feature.jpg" alt="" title="" width="626" height="261" />
$src_start = strpos($image, 'src="') + 5;
$src_end = strpos($image, '"', $src_start);
$src = substr($image, $src_start, $src_end - $src_start);
?>