You can display the image locally before uploading it to the server by selecting Local Uploaded (Widget State) in the Store media for upload Action and Uploaded file in the Image Type of the Image widget.
However, in the case of Video, the Uploaded file cannot be selected in the Video Widget, so it cannot be displayed before it is uploaded to the server.
Does anyone know of a way to view a video's Local Uploaded or see a thumbnail image, etc. before it's uploaded to the server?