def [](*args)
      a = @images[*args]
      if a.respond_to?(:each)
        ilist = self.class.new
        a.each { |image| ilist << image }
        a = ilist
      end
      a
    end
def [](*args)
      a = @images[*args]
      if a.respond_to?(:each)
        ilist = self.class.new
        a.each { |image| ilist << image }
        a = ilist
      end
      a
    end
Compare ImageLists
 Compare each image in turn until the result of a comparison
 is not 0. If all comparisons return 0, then
   return if A.scene != B.scene
   return A.length <=> B.length