NSDraggingImageComponent class represents a single object in a dragging item.
An array of
NSDraggingImageComponent instances are composited together to create the dragging image for an
NSDraggingImageComponent instances can simply be considered as named images with a location used by an
NSDraggingItem for more information.
Creating a Dragging Image Component
Initializes and returns a dragging image component with the specified key.