Reply To: Image ALT tag from media library

function slider_output($atts) {
extract( shortcode_atts( array(
    'img' => '',
), $atts ) );
   
global $post, $wpdb;
     
$images = get_post_meta($post->ID, $img, false);
$out = '';
foreach ($images as $image) {
$attachment_id = $wpdb->get_var($wpdb->prepare(
"SELECT ID FROM $wpdb->posts WHERE guid = %s",
$image
));
$image_title = get_the_title($attachment_id);
$thumb = wp_get_attachment_image_src( $attachment_id, ('slider-image') );
$alt = get_post_meta($attachment_id, '_wp_attachment_image_alt', true);
$out .= '<img itemprop="image" src="' . $thumb[0]. '" alt="' . $alt . '" />';
}
$out .= '';
return $out;
}
add_shortcode('slider-output', 'slider_output');

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