The court shall, if judgment be rendered for the plaintiff, cause any defendant who refuses or fails to pay forthwith the amount of the judgment rendered against him and all the costs and charges incident thereto, to be committed to the county jail for a period of not less than thirty days nor more than ninety days, except in cases where the penalty is five hundred dollars ($500.00), in which cases commitment shall be made for a period of not less than sixty days nor more than one hundred fifty days.
N.J.S. § 45:6-26