Hi,
There is a much easier solution, that will work with both plugin versions, and will retain during updates as well. The developer correctly identified the files, and since there is a very clever function in his plugin to get the image URL, I can easily construct a custom code based on that.
Add this custom code to the functions.php in your theme/child theme directory (copy from line 3 only!). Before editing, please make sure to have a full site back-up just in case!