Thank you Pictureplace Luxiary!

At this point you know for sure that you have at least three images:

1. yourimage@s_1920.jpg
2. yourimage@s_720.jpg
3. yourimage@s_100.jpg

so you can just compose your image path with the Firebase Storage SDK!
As an example:

const myImage = `path/to/image@s_1920.jpg`