Several studies show that social image concerns stimulate prosocial behavior. We study a setting in which there is uncertainty about which action is prosocial. Then, the quest for a better social image can potentially conflict with genuinely prosocial behavior. This conflict can induce “bad” behavior, where people lower both their own and others' material payoffs to preserve a good image. This setting is relevant for various types of credence goods. For example, recommending an inexpensive treatment reduces the expert’s profits and may not satisfy the true needs of the client, but is generally good for the expert’s image (as it signals the lack of greed). We test experimentally if people start to act bad in order to look good. We find that people care about their social image, but social image concerns alone do not induce them to act bad. That is, without future interactions, social image concerns do not lead to bad behavior. However, with future interactions, where building up a good image has instrumental value (reputational concerns), we do find evidence of bad behavior in the short run to secure higher earnings in the long run.