// tablet
    add_retina_image_size('img_768', 768);
    // phone
    // Banner
    add_retina_image_size('img_825', 825);
    // desktop
    add_retina_image_size('img_825', 825);
    // small desktop
    add_retina_image_size('img_992', 992);
    // tablet
    add_retina_image_size('img_768', 768);
    // phone
    // Generic/Announcements
    add_retina_image_size('img_324', 324);
    // desktop
    add_retina_image_size('img_258', 258);
    // small desktop
    add_retina_image_size('img_184', 184);
    // tablet
    add_retina_image_size('img_681', 681);
    // phone
    // Single Featured Image
    add_retina_image_size('img_825', 825);
    // desktop
    add_retina_image_size('img_675', 675);
    // small desktop
    add_retina_image_size('img_690', 690);
    // tablet
    add_retina_image_size('img_707', 707);
    // phone
}
add_retina_image_size('img_460', 460);
// desktop
add_retina_image_size('img_376', 376);
// small desktop
add_retina_image_size('img_345', 345);
// tablet
add_retina_image_size('img_768', 768);
// phone
// Centered Images
add_retina_image_size('img_950', 950);
// desktop
add_retina_image_size('img_783', 783);
// small desktop
add_retina_image_size('img_720', 720);
// tablet
add_retina_image_size('img_768', 768);
// phone
if (!function_exists('retina_images_shortcode')) {
    function retina_images_shortcode($atts)
    {
        $classes = array('retina-shortcode');
        extract(shortcode_atts(array('id' => '', 'caption' => 'false', 'class' => '', 'align' => 'center'), $atts));
        $classes = array_merge($classes, explode(' ', $class));
        $img_sizes = array(460, 376, 345, 768);
        if ($align == 'left' || $align == 'right' || $align == 'center') {
            $classes[] = 'align' . $align;
            if ($align == 'center') {
                $img_sizes = array(950, 783, 720, 768);
            }
        }
        $classes = implode(' ', $classes);