After quite a bit of trial and error, I got the code set up correctly for the WordPress loop. I put it into a shortcode. Here it is:
add_shortcode( 'partnerlogos', 'display_partner_logos' );
function display_partner_logos(){
// Define the query
$args = array(
'post_type' => 'dnf_partner_logos',
'post_status' => 'publish'
);
$query = new WP_Query( $args ); ?>
<!-- Carousel
================================================== -->
<div id="partnersCarousel" class="carousel slide">
<div class="carousel-inner">
<?php $count = 0;
while ($query->have_posts()) : $query->the_post();
$image = get_field('partner_logo');
$url = $image['url'];
$size="dnf-partners";
$thumb = $image['sizes'][ $size ];
$width = $image['sizes'][ $size . '-width' ];
$height = $image['sizes'][ $size . '-height' ];
if($count % 4 == 0) { ?>
<div class="item <?php if($count == 0) echo "active"; ?>">
<div class="row">
<?php } ?>
<div <?php post_class("col-md-3") ?> id="post-<?php the_ID(); ?>">
<a href="#" class="thumbnail">
<img src="https://wordpress.stackexchange.com/questions/217096/<?php echo $thumb; ?>" class="img-responsive" alt="Thumb11">
</a>
</div>
<?php if($count % 4 == 3) { ?>
</div>
</div>
<?php }
$count++;
endwhile;
if($count % 4 != 0) { ?>
</div>
</div>
<?php } ?>
</div>
<a class="left carousel-control" href="#partnersCarousel" data-slide="prev"><i class="fa fa-chevron-left fa-2x"></i></a>
<a class="right carousel-control" href="#partnersCarousel" data-slide="next"><i class="fa fa-chevron-right fa-2x"></i></a>
</div>
<?php
wp_reset_postdata();
wp_reset_query();
}