Export a picture of the selected strokes of grease pencial to PNG

I’m working on an automatic animation assistant. (aka. Cinematic Quality Auto Inbetweening.)

I use a neuronal network to do the process, so I require 2 PNG images to generate the flow between the images.

Does anyone know how to export the selected lines and filler?

https://4232.cf/es/quinema-your-animation-assistant/