<?php
// get an array of multiple values
$post_meta_array = get_post_meta($post->ID, \'link\'); // do not use \'true\' as the third argument
// echo the link for each value 
foreach ($post_meta_array as $post_meta) {
    echo \'<a href="\' . $post_meta . \'" target="_blank">Images Source</a>\';
}