An image is an artifact that depicts or records visual perception, for example a two-dimensional picture, that has a similar appearance to some subject–usually a physical object or a person, thus providing a depiction of it.
A still image is a single static image. This phrase is used in photography, visual media and the computer industry to emphasize that one is not talking about movies, or in very precise or pedantic technical writing such as a standard.
A moving image is typically a movie (film) or video, including digital video. It could also be an animated display such as a zoetrope.
A still frame is a still image derived from one frame of a moving one. In contrast, a film still is a photograph taken on the set of a movie or television program during production, used for promotional purposes.