Comment 3 for bug 1403129

Storing uploaded files in /tmp is an inherent property of the Django file-uploading machinery: https://docs.djangoproject.com/en/1.6/topics/http/file-uploads/#where-uploaded-data-is-stored

While streaming file contents directly to glance would certainly free up some space on controller, it would also raise the question on how to perform form validation in this case.