Indirect reciprocity is a mechanism which might provide a solution to the puzzle of how cooperation has evolved. Image scoring is a simple first-order assessment rule which bases an individual's reputation only on its past behavior. If reputation is binary (either "Good" or "Bad"), then conditional cooperation is evolutionarily stable under some higher-order assessment rules, but not under image scoring, which has led to a dismissal of the scoring rule. Here we show that introducing "Neutral" alongside Good and Bad types allows conditional cooperation to persist under image scoring.