def print_img(narr=@narray)
      puts "Image dimensions: #{@columns}*#{@rows}"
      narr.shape[0].times do |i|
        puts narr[true, i].to_a.to_s
      end
    end
def print_img(narr=@narray)
      puts "Image dimensions: #{@columns}*#{@rows}"
      narr.shape[0].times do |i|
        puts narr[true, i].to_a.to_s
      end
    end
A convenience method for printing image information.

 @deprecated NB! This has been used only for debugging, and will soon be removed.
 @param [NArray] narr a numerical array