Randomly show post attachment

Hi
The best way to explain is to show my code :

<?php
if (have_posts()) :
$c = 0; while ( have_posts() ) : the_post(); $c++;
if ( $c == 1) {
$style = “current first”;
}
elseif ( $c == count( $posts ) ) {
$style = “last”; } /*
elseif ( $c == 2 ) {
$style = “”; }*/

else $style =’dispa’;

?><?php
$images =& get_children( array (
‘post_parent’ => $post->ID,
‘post_type’ => ‘attachment’

));
foreach ( $images as $attachment_id => $attachment ) {

?><div <?php post_class($style) ?>id =”post_<?php echo $post->ID;?>”><?php echo wp_get_attachment_image( $attachment_id, ‘large’ ); }

?><div <?php post_class(‘mezzanine ‘ . $style) ?>><?php $description = $attachment->post_content;
echo $description;
?></div></div><?php
endwhile;
wp_reset_postdata();
else :
echo wpautop( ‘Sorry, no posts were found’ );
endif;
?>

The result of this is to show the attachement image that is directly attached to the current post.
I want to show the posts / posts attachments in random order though i noticed that adding the ‘orderby’ => ‘rand’ function is not helping.
Does anyone could help me with this?
Thank you in advance

if you want to see the actual result you can go on https://blog.dansayag.com

The blog I need help with is blog.dansayag.com.