img tag not converted to amp-img

I am not talking about the featured image…. check the regular images on the post.

Yes,
Using the ACF WP plugin.
I have a few custom fields and I created the following template for the post with these fields. This is the template (as you can see, it has tags which are not converted to amp-img):

<?php
$introduction = get_field(‘introduction’);

if (isset($introduction) && trim($introduction)!=” && trim($introduction)!='<p></p>’) {?>
<div class=”amp-wp-article-content”>
<p><?php echo get_field(‘introduction’); ?></p>

<div class=’topics-summary’>
<h5>In this article:</h5>

<?php while( have_rows(‘section_list’) ): the_row(); ?>
<?php $title = get_sub_field(‘section_title_h2’); ?>
<?php $reftitle = str_replace(” “, “-“, $title); ?>
1. “><?php echo $title ?>

<?php endwhile; ?>

</div>

<?php while( have_rows(‘section_list’) ): the_row(); ?>

<?php $linkedpost = get_sub_field(‘section_linked_post’); ?>
<?php $postlink = get_permalink($linkedpost->ID); ?>
<?php $posttitle = get_the_title($linkedpost->ID); ?>

<?php $title = get_sub_field(‘section_title_h2’); ?>
<?php $reftitle = str_replace(” “, “-“, $title); ?>

<h2>‘><?php echo $title; ?></h2>
<p><?php echo get_sub_field(‘section_content’); ?></p>
<?php if ($linkedpost != false) { ?>
<div class=’section-read-more’><b>More on </b>“><?php echo $posttitle ?></div>
<?php } ?>
<?php endwhile; ?>
</div>
<?php
}
?>