Question:
Amazon S3: under a pre-created bucket, how to create a sub-folder and insert the file into that folder ?
See http://stackoverflow.com/questions/1939743/amazon-s3-boto-how-to-create-a-folder
"There is no concept of folders or directories in S3. You can create file names like "abc/xys/uvw/123.jpg", which many S3 access tools like S3Fox show like a directory structure, but it's actually just a single file in a bucket."