This code shows how to read and write blobs and how to create a serving url.
The blobfiles can be images or other files like css, js and pdf's.
We use the default bucket in Google Cloud Storage (GCS) to store the blobs.
From the docs: An application can use the default GCS bucket, which provides an already configured bucket with free quota.
This code still needs the blobstore.create_gs_key() for images.get_serving_url()
We use an image serving url for dynamic resizing and cropping.