/*
 * Returns a new Imlib2::Image with the specified width and height.
 *
 * Examples:
 *   width, height = 640, 480
 *   image = Imlib2::Image.new width, height
 *
 *   width, height = 320, 240
 *   image = Imlib2::Image.create width, height
 */
VALUE image_new(VALUE klass, VALUE w, VALUE h) {