def reject(&block)
      current = get_current
      ilist = self.class.new
      a = @images.reject(&block)
      a.each { |image| ilist << image }
      ilist.set_current current
      ilist
    end
def reject(&block)
      current = get_current
      ilist = self.class.new
      a = @images.reject(&block)
      a.each { |image| ilist << image }
      ilist.set_current current
      ilist
    end
override Enumerable's reject