I was having a lot of trouble with this as well, especially with the attached images. Here is what I ended up with:
<?php
$rows = get_field('partners');
if($rows) $i = 0; {
shuffle( $rows );
foreach($rows as $row) {
$i++; if($i==6) break;
$image = $row['partner_logo']; ?>
<li class="partners-list-item desaturate"><img src="<?php echo $image; ?>" alt="" /></li>
<?php } } ?>