Use the import/media hot folder to add media files directly to the server and content database instead of having to click Import in the UI. Successfully imported files are moved to the root media folder. If you previously added a TBD placeholder for a file, the file will attach when you move it into import/media. The only sub-folder is a “failed” folder (directory) where files that fail to import are moved.
Transfer time depends on the size of the file and the network speed.