Different light types - back light
This multiple category is in fact one type of light, namely, backlight. As the name suggests, the light source is positioned behind the subject and depending on circumstances such as the intensity of the light and whether additional light sources or reflections are trained on the subject, the result could be a silhouette or a rim light which resembles a halo effect.
The photograph taken from within the cave is illuminated solely with light from the background sky area. This forces the framework of the cave and the figure into total silhouette.
In the picture of the girl, although she is backlit the sun is positioned at an angle to her, enabling its light to define her outline and also pass through the finer areas of her hair forming a rim light effect.