In June 2004, the jury of the VI Bienal de Fotoperiodismo gave a prize to the work "Mexicaltzingo comunidad en rebeldía" by Giorgio Viera. One of the photographs contained in the essay "Alma en la azotea" generated an intense polemic as by many it was considered plagiarism, posed and therefore false. Others considered that its transcendence and expressive force could not be judged as false or true. The debate made evident the urgency to clarify the meaning of truth, credibility or reality when talking about images and their relation with ethics. The catalogue of the biennial integrated a series of texts related to this old problem. This anthology includes some of those articles.