Hi borisrgey,
You can open the \ja_teline_v\html\layouts\joomla\content\image\image.php file and find the line 36:
Try with the following code:
<span itemscope itemtype="https://schema.org/ImageObject">
<img src="<?php echo htmlspecialchars($img); ?>" alt="<?php echo htmlspecialchars($alt); ?>" itemprop="url"/>
<?php if (!empty($caption)) { ?>
<meta itemprop="caption" content="<?php echo htmlspecialchars($caption); ?>" />
<?php } ?>
</span>
