The field group is inside the loop; it’s in a single template for a custom post type. It’s also inside an if/else statement that returns either a single photo or a gallery, if there is one. As I said, everything else is working (apparently) flawlessly.
This is the context:
<?php
if ( get_field('gallery')) { ?>
<div class="gallery">
<div id="imageview">
<?php
$rows = get_field('gallery' ); // get all the rows
$first_row = $rows[0]; // get the first row
$first_row_image = $first_row['gallery_photo' ]; // get the sub field value
// Note
// $first_row_image = 123 (image ID)
$image = wp_get_attachment_image_src( $first_row_image, 'full' );
// url = $image[0];
// width = $image[1];
// height = $image[2];
?>
<img src="<?php echo $image[0]; ?>" alt="why isn't this working?" />
</div>
<div id="thumbnails">
<?php if( have_rows('gallery') ): ?>
<?php while ( have_rows('gallery') ) : the_row(); ?>
<a href="<?php the_sub_field('gallery_photo'); ?>"><img src="<?php the_sub_field('gallery_photo'); ?>" alt="" /></a>
<?php endwhile; ?>
<?php endif; ?>
</div>
</div>
<?php } else { ?>
<div class="listingPhoto">
<img src="<?php the_field('listing_photo'); ?>" />
</div>
<?php }
?>
…and this is what’s being returned:
<div class="gallery">
<div id="imageview">
<img src="" alt="why isn't this working?" />
</div>
<div id="thumbnails">
<a href="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh.jpg"><img src="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh.jpg" alt="" /></a>
<a href="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh4.jpg"><img src="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh4.jpg" alt="" /></a>
<a href="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh5.jpg"><img src="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh5.jpg" alt="" /></a>
<a href="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh3.jpg"><img src="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh3.jpg" alt="" /></a>
<a href="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh2.jpg"><img src="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh2.jpg" alt="" /></a>
<a href="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh7.jpg"><img src="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh7.jpg" alt="" /></a>
<a href="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh6.jpg"><img src="http://stevedowty.com/sunshine/wp-content/uploads/2017/03/mh6.jpg" alt="" /></a>
</div>
</div>
The URL is http://stevedowty.com/sunshine/listings/518-crestview-drive/
