add_shortcode('mijnpress_mediaid_to_url', 'mijnpress_mediaid_func');
function mijnpress_mediaid_func($atts)
{
return wp_get_attachment_url(intval($atts['id']));
}
Usage for custom field header_logo
<img src="[mijnpress_mediaid_to_url id=[wpv-post-field name="header_logo"]]" class="img-responsive img-center">