How to dynamically register image thumbnails

I want to add image thumbnails from different bundles without the need to define them inside the backend.

I tried using rewriting the image-thumbnails.php file from the AppBundle::boot() method. Is this even the right approach?

Better use the Installer and actually add them to the config.

Oh that sounds like a good idea! Thx for the pointer. I’m using an Installer already but how can i add the thumbnail definitions to the config?

Thx so far.