def generate_srcset(piece)
        piece.styles.map do |name, width|
          if piece.image.attachment.exists?(computed_style(piece, name).to_sym)
            "#{piece.image.attachment.url(computed_style(piece, name).to_sym)} #{width}w"
          else
            "#{piece.image.attachment.url(:original)} #{width}w"
          end
        end.join(', ')
      end
def generate_srcset(piece)
        piece.styles.map do |name, width|
          if piece.image.attachment.exists?(computed_style(piece, name).to_sym)
            "#{piece.image.attachment.url(computed_style(piece, name).to_sym)} #{width}w"
          else
            "#{piece.image.attachment.url(:original)} #{width}w"
          end
        end.join(', ')
      end
Build the srcset values from the list of piece styles (2000px-200px)