extract_dimensions

# File actionview/lib/action_view/helpers/asset_tag_helper.rb, line 483
        def extract_dimensions(size)
          size = size.to_s
          if /\A\d+x\d+\z/.match?(size)
            size.split("x")
          elsif /\A\d+\z/.match?(size)
            [size, size]
          end
        end