Get the Lh3. Googleusercontent. Com Link of Every Slide via Google Apps Script

I have seen some of the Slide addons that bring every Slides for offline processing (as GIF/Video etc)

There are links that render as image for every slide in this slide file

lh3.googleusercontent.com

Like for example for the slide has for each of the slides so the addon uses to create a GIF from a Client JS Library fetching

Could anyone explain how to fetch the lh3.googleusercontent.com URL of every slide files.