The preferred way to export an image to Cloud Storage is to use the gcloud compute images export command.
This command uses Daisy to chain together the multiple steps that are required to export an image.
Using the gcloud command-line tool, run:
gcloud compute images export --destination-uri [DESTINATION_URI] \
For example, the following command exports an image named my-image from my-project to a Cloud Storage bucket named my-bucket. By default, the image is exported as a disk.raw file and is compressed into the tar.gz file format.
gcloud compute images export --destination-uri gs://my-bucket/my-image.tar.gz \
--image my-image --project my-project