Responsive images shortcode

I have read an article a bout responsive image and shortcode in Hugo at https://news.ycombinator.com/item?id=12673598. Can someone show me how can I use that shortcode? I am not a software engineer so I dont understand that code. Thank you verymuch

This looks a little tricky, at least in terms of what is include in the pastebin reference from ycombinator. It might be easier to make your own, but this depends…what are you using to resize your images and what sizes are you outputting?