At what point are images of ourselves true or untrue?

We tend to try to hold onto images of ourselves in relationship to others. I think images give general impressions of how we contribute to others... how we interact with them. But at the same time each moment and each interaction can be different from the next. So at that point is the image of some generality true? And what happens when so much focus goes into defending images? It seems like a lot of energy to defend something that might not really exist.