I modified the script as below and it worked... Thank you so much for the help.
enter code here
function portfolio_small_single($id){
$meta_value = get_post_meta($id, '_port_data', true);
$return = '<ul id="small_thumb_lists">' . "\n";
if( $meta_value != ""){
foreach( $meta_value as $i => $data ){
if(!empty($data)) {
$return .= '<li><a href="'.$data.'">' . "\n";
if(!linkisimage($data)){
$data = str_replace("http://crizaze.com", "", $data);
$return .= '<img src="' . get_bloginfo('template_url') . '/timthumb.php?src=' . $data . '&h=80&w=80&zc=1" alt="" />';}
else
$return .= '<img src="' . get_bloginfo('template_url') . '/images/vid80.jpg" width="80" height="80" alt="" />';
$return .= '</a></li>' . "\n";
}
}
}
$return .= '</ul>' . "\n";
return $return;
}