The app receives messages from the operating system when folders change. So, it updates whenever it gets a message. However, those messages are very “chatty”, so the app has code to prevent it from constantly refreshing.
Edit with External App: You pick an app from the list. The app provides you with some choices for how to render the image to send to the app (JPEG, TIFF, etc). The image is made and sent to the other app. The app modifies the file and the image updates in RAW Power.
HOWEVER, this assumes that the external app actually modifies the file. If it creates a project file (e.g., photoshop or Pixelmator), then it’s not modifying the file. In that case, you have to export the file to get it to show up in RAW Power.
