Imageslider with thumbnails

[jsr4id]

Hi i use the Quantom Manager extension.
First of all, realy nice work and you have a good documentation about it!
I'd like to realize a image slider with thumbnails via the embeded files button.
Similar like this :
https://mdbootstrap.com/snippets/jquery/ascensus/135500

Problem is, that the src="{file}" tag also need to be in the after section for the thumbnails.
I thought i can do this with the Before and After template override.

Do You have an idea?