The Photographic Archive was created in 2007, as a section of the Association's Historical Archive, to recover all the photographic heritage dispersed to all areas of the COAC. The aim was thus to prevent its loss or deterioration due to lack of good storage conditions and installation.

Today the Photo Archive has a volume large enough to consider it one of the best architectural image files of the country.

Among others, the Archive includes three major collections of images gathered from the creation of the Historical Archive and organized thematically, onomastically and geographically; photographers' archives such as Francesc Catala-Roca's and Oriol Maspons; Lluis Domenech i Montaner's collection of photographs of Romanesque works; glass plate negatives of Gaudi's workshop; and vintage positives attributed to Opisso.