This paper proposes the use of the DStretch image analysis tool applied to the study and formal analysis of eighteenth-century mural paintings in the San Agustín Church of San Cristóbal de La Laguna, a World Heritage city in Spain. Thanks to the technification of digital documentation, it has been possible to recover virtually this pictorial group that currently is almost completely lost due to a fire occurred in 1964. A work methodology that aims to achieve a reliable and rigorous recreation is proposed, supported by free software DStretch. This tool, which is conceived for research on rock art, is based on decorrelation processes, used in digital image treatment, which improve the readability of an image. The method offers an interesting applicability to the study of the historical mural painting analyzed and enhance the objectivity of its virtual reintegration.