Photo and Video Preview
When you capture a photo or a video, a small version of it appears at the side of the screen. It is there so you can check what you captured without leaving the camera.
While that thumbnail is showing, say “PREVIEW” to open it full size.
The thumbnail always shows the most recent capture, so saying “PREVIEW” opens whatever you took last. Once it has gone from the screen, open the file from My Files instead: say “MY FILES” from the camera, or find it in the Camera folder in My Photos for a photo, or My Media for a video.