Go ahead log in to your WordPress Dashboard, then go to Avada > Theme Options > Advanced > Code Fields.
Next, add the code in the Space before </head> box.
<script>
jQuery(document).ready(function($) {
$('img[title]').each(function() { $(this).removeAttr('title'); });
});
</script>
That’s it! And a reminder to always make a backup first 😉