A silhouette is a representation of dark through light. An outline of a landscape, object or person. Where the main focus is on the darkness of the bright image within the same photograph. Where the subject, significant element or supporting feature is the dark premise in the image.
For the Shadows aspect, if the point-of-view is effected by the shadows, then its suitable for this group. So the image would look differently if there were less shadows or seen from another point-of-view. All images have shadows; though, these shadows add a new perspective which add to the image. Like in old films where the man or woman's face is half lit, and half in the shadow, the director is sharing with the audience just by how the character is illuminated, that we are only seeing one perspective of the overall view. That is what I am looking for in this group. That added dimension.