We test whether individuals internalize the effects that their behavior may have on the social image of their group. In our experiment, we recruit pairs of real-life friends and study whether rule breaking in the form of misreporting decreases when misreporting may have negative spillovers on the image of the friend. We find that participants hurt their friends' social image by misreporting because external observers update their beliefs: they rightfully expect that a participant whose friend misreported is likely to misreport himself. However, participants misreport as often when their behavior can hurt the friend's image as when it cannot, even though hurting their friends' image reduces their own monetary gains. Our interpretation is that they underestimate the impact of their behavior on external observers' beliefs about their friends. Our results cast doubts on the capacity of groups to sustain a good image absent the possibility of punishment, which is bad news. The good news is that external observers may use image spillovers to update their beliefs and interact with members of social groups more efficiently.