Let’s say foo.com is also available on mobile devices, which need images rendered in smaller mobile formats. You can decouple functionality like this from the web server and make it a function-as-a-service with Cloud Functions. This approach enables you to apply your image resizing logic to other applications as well. You can trigger the serverless function as soon as a file is added to Cloud Storage and convert the file into multiple formats and put them back into storage, where they are used by the web server. You could also use serverless functions for other use cases such as address lookups, chatbots, machine learning, and more.