Imported From: http://groups.google.com/group/in-portal-dev/browse_thread/thread/d3d46d605743a01b#
To be able to upload something it's required to create target folder (once
per field) and "/resized" subfolder under it and set proper write
permissions on them. Then created folder name should be specified in
corresponding field declaration in unit config. This is potential place for
typing errors, because developer could:
...