knees out of frame
Images where the subject's whole body down to and including the upper legs are in the frame, as are the character's lower legs, but the knees are mostly or entirely outside of it.
If the lower legs and feet are out of the frame as well, the image should be tagged with cowboy shot instead.
Most often occurs with characters who are kneeling, sitting or squatting, as these poses most often give the bend of the legs necessary for this.