list of attachments: wp_get_attachment_link works, wp_get_attachment_image does not

Question

On single.php theme template file, I'm displaying the post's list of attachments.

global $post;
$args = array(
    'post_type' => 'attachment',
    'numberposts' => null,
    'post_status' => null,
    'post_parent' => $o_ID
);
$attachments = get_posts($args);
if ($attachments) {
    echo '<ul class="slideshow-controller">';
    foreach ($attachments as $attachment) {
        //echo apply_filters('the_title', $attachment->post_title);
        echo '<li>';
        echo wp_get_attachment_link($attachment->ID, 'thumbnail', 0, 0, 'Download');
        echo wp_get_attachment_image($attachment->ID, 'thumbnail',false);
        echo '</li>';
    }
    echo '</ul>';
}

Weird, wp_get_attachment_linkworks correctly (echoes the attachment's media link), wp_get_attachment_imagedoes not: it echoes nothing at all.

What am i doing wrong?

Answer 1

Replace the line

echo wp_get_attachment_image($attachment->ID, 'thumbnail',false);

with

echo $attachments['post_content'];