The title attribute on an image will appear when a user hovers their mouse over an image while viewing the website. Jimdo does not provide a way to enter a title attribute, only a caption (which appears below the image) and an alt tag.
The following code will take any alt tags that are set on a Jimdo website and enter them as the title tags as well.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js" type="text/javascript">
</script>
<script type="text/javascript">
//<![CDATA[
$(document).ready( function() { $('img').each(function(i, el)
{ var alt = $(el).attr('alt'); if (alt) { $(el).attr('title', alt); } }); });
//]]>
</script>