ImageProducer Methods
n addConsumer(ImageConsumer ic) This method is used to
register an ImageConsumer with the ImageProducer for
access to the image data during a later reconstruction of the
Image.
n removeConsumer(ImageConsumer ic) This method
removes the given ImageConsumer object from the list of
consumers currently registered to receive image data.
n startProduction(ImageConsumer ic) This method   starts an
immediate reconstruction of the image data