To take a photograph of a person is to lay bare their identity to the eyes of others. The photograph generates an ambiguous relationship with the idea of identity. It can in turn lay it bare, exploit it, reveal and embody it. It creates an image which takes on its own existence separately from the person portrayed. It can become a source of profit, a cause of moral harm, a means of proof, and an object of cupidity. The question which arises is: how can we know when it is legitimate to use a photograph? The law protects the person's legitimate interest, but does not only protect private interests, it also watches over the common good, and the interest of society as a whole justifies a certain number of uses of a person's photograph without their consent. This article has been written in order to clarify the ethical and legal conflicts from a French perspective, which the physician has to confront when obtaining consent from a patient before taking a photograph. Awareness of these points should make it possible to avoid any problems which could arise in relation to publications which carry illustrations for the purpose of increasing their impact.