global $query_string;
$query_args = explode("&", $query_string);
$search_query = array();
foreach($query_args as $key => $string) {
    $query_split = explode("=", $string);
    $search_query[$query_split[0]] = urldecode($query_split[1]);
}
$custom_query = array();
$custom_query['tax_query'][] = array( 'taxonomy' => 'image', 'field' => 'slug', 'terms' => array('image'), 'operator' => 'NOT IN' );

$args = array_merge( (array)$search_query, (array)$custom_query );
print_r( $args );
query_posts( $args );

if ( have_posts() ) : ?>