code: def create_color_string
        (0...img.height).map do |y|
          (0...img.width).map do |x|
            pix = self.img[x,y]
            pix_vals = [r(pix), g(pix), b(pix)]
            find_closest_term_color(pix_vals)
          end
        end.join
      end
docs: Iterates over each pixel of resized image to find closest color