Drupal Deployment
If you have a live site and a stage (or dev) site, you will probably want to add any new files (such as images) from the files directory on the live site to the staging site, or vice versa.
Creating an effective deployment process has historically been a nightmare with Drupal. A deployment process should include pushing content and configuration settings (and code) from dev server to stage server to live server. In many cases, pushing content from live server back to stage server will also be required (to test on the stage server with real life content).
See Demonstration of Drupal deploy module Video