Redirect Attachment Pages to Parent Post
add_action('template_redirect', 'attachment_redirect');
function attachment_redirect() {
global $post;
if (is_attachment() && isset($post->post_parent) && is_numeric($post->post_parent) && ($post->post_parent != 0)) {
wp_redirect(get_permalink($post->post_parent), 301);
exit;
}
}