Organizational identity concerns within the organization and how members see their organization, While Organizational image related to others and their beliefs about the organization.
maybe you want to look at articles such as by Hatch and Schultz (2002) and Dutton and Dukerich (1991). Although Salam is right when he says that there is a difference between the two, you should know that the two constructs are interdependent and co-created. Also, be careful how you define the terms image and identy as both of them might mean different things to different people.