I have the same problem!
You can edit the line #429 in the file
/plugins/wp-tiles/src/WPTiles/WPTiles.php
with this code:
<img src='<?php echo $img ?>' alt='<?php echo $byline ?>' class='wp-tiles-img' itemprop="image" />
Take a look here:
http://www.lanaebiscotti.it/
I have used the $byline variable configured as the title of the post in the plugin options. I think is possible also with $title variable.
