Infojus Noticias has a great piece on Adelina Dematti, a member of the Mothers of the Plaza de Mayo who photographed the group's struggle using a Kodak hidden under her clothes. She said she did it so that her disappeared son Carlos "would know he was not alone, that we were looking for him". She never found out what happened to him.
Her act of recording meetings and demonstrations was extremely dangerous under the dictatorship and provides us with a record of the Madres movement from an insider's perspective. The Madres are now active on social media and I think we can be sure if those options had been available to them in the 1970s and 80s, they would have used them, but as it is, Dematti's photos are unusual.
She photographed the Mothers' gatherings, the participation in the large Marches of Resistence, meetings with Nobel peace prize winner Adolfo Pérez Esquivel, writer Julio Cortázar and, later, president Néstor Kirchner. I particularly like the picture of the 1983 Marcha de la resistencia showing the silhouette cutouts of the disappeared - the "silouetazo".
See more here:
Las fotos de Adelina, la Madre que documentó la búsqueda de su hijo (Infojus Noticias)