imagefield and temp files?
In file settings you specify a temp path and a files path, which is what is used by Drupal.

The temp path which could be /tmp, but it could also be default/files that is entirely up to you. the temp file folder is where files are uploaded to after being submitted in a form. After validation checks, file_save_upload should be used to save the file. There is no reason for the file to be saved to the default/files folder and then be moved, as it can be saved directly to whichever folder you want. I do believe that is how the imagemodule does it..