While people frequently behave prosocially, they also tend to avoid situations that call for prosocial behavior. We study this phenomenon in the context of a donation request in the absence of social interactions, thereby focusing on the effect of self-image motivation. We conduct an incentivized online experiment involving two consecutive dictator games with a charity. In the first stage, we employ a 2×2 between-subject design, varying the characteristics of the dictator game and the information provided: (i) standard dictator game or dictator game with a costly opt-out, and (ii) with or without social information (mean donation in a previous session). The second stage is a standard dictator game for all participants. We find that the opt-out option leads to significantly fewer donations to the charity, supporting our hypothesis that opting out is a strategy to preserve the self- image while not donating. The provision of social information increases opt-outs, although not statistically significant. Finally, we observe distinct behaviors in the second stage based on the options and decisions in the first stage, suggesting a role for self-image motivation in temporal dynamics of prosocial behavior.