What's the etiquette with .webp image files?

Hi all,

Before I start upgrading images to the webp format, how should I go around adding a backup in case the browser does not support the format? I know that you can simply solidly set them using .webp instead of .png, but was wondering how I should go around supporting webp files and keeping support for legacy browsers?


This might be illuminating:


Thank you very much!