Fulltext image on module override (example with mod_articles_latest)

default.php

<?php
/**
 * @package     Joomla.Site
 * @subpackage  mod_articles_latest
 *
 * @copyright   (C) 2006 Open Source Matters, Inc. <https://www.joomla.org>
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

defined('_JEXEC') or die;

use Joomla\CMS\Layout\LayoutHelper;

if (!$list)
{
	return;
}

?>
<ul class="mod-articleslatest latestnews mod-list">
<?php foreach ($list as $item) : ?>

	<?php
		$images = json_decode($item->images);
		$item->imageSrc = '';
		$item->imageAlt = '';
		$item->imageCaption = '';
		$item->imageSrc = htmlspecialchars($images->image_fulltext, ENT_COMPAT, 'UTF-8');
		$item->imageAlt = htmlspecialchars($images->image_fulltext_alt, ENT_COMPAT, 'UTF-8');
		if ($images->image_intro_caption)
		{
			$item->imageCaption = htmlspecialchars($images->image_fulltext_caption, ENT_COMPAT, 'UTF-8');
		}
	?>

	<li itemscope itemtype="https://schema.org/Article">
		<a href="<?php echo $item->link; ?>" itemprop="url">
			<span itemprop="name">
				<?php echo $item->title; ?>
			</span>
			<figure class="newsflash-image">
				<?php echo LayoutHelper::render(
					'joomla.html.image',
					[
						'src' => $item->imageSrc,
						'alt' => $item->imageAlt,
					]
				); ?>
				<?php if (!empty($item->imageCaption)) : ?>
					<figcaption>
						<?php echo $item->imageCaption; ?>
					</figcaption>
				<?php endif; ?>
			</figure>
		</a>
	</li>
<?php endforeach; ?>
</ul>