The rare piece is in decent vintage condition; there are expected superficial imperfections and scratches on the surface as well as micro spots of rust; back side has traces of some adhesive and appears to be previously mounted on something (possibly even framed). The piece is otherwise nicely preserved. 

A NOTE of HISTORY OF RETABLO FOLK ART:  Votive paintings in Mexico go by several names in Spanish such as “ex voto,” “retablo” or “lamina,” which refer to their purpose. The painting of religious images to give thanks for a miracle or favor received, is part of a long tradition started in Europe. The form that most votive paintings take from the colonial period to the present was brought to Mexico by the Spanish. As in Europe, votive paintings began as static images of saints or other religious figures which were then donated to a church. Later, narrative images, telling the personal story of a miracle or favor received appeared. These paintings were first produced by the wealthy and often on canvas; also on wood; however, as sheets of tin became affordable, lower classes began to have these painted on this medium. The narrative version on metal sheets is now the traditional and representative form of votive paintings. Though some ex votos have been painted by the person receiving the miracle, most are made by retableros: commissioned artists who interpret people's stories and produce these tokens of appreciation to be placed/hung on church walls or shrines, reinforcing the owner's devotion and gratitude. These lovely miracle paintings are in fact advertisements of the power and mercy of the saints. Due their proliferation, especially in the 18th and 19th century, many older votive paintings have left the places they were deposited and found their way into public and private collections. The collecting of tin retablos was begun by Mexican artist Diego Rivera, whose work, along with those of a number of other painters past and present, has been influenced by them. (See last photo showing collection of retablos in the Museum of Frida Kahlo in Mexico City - "Casa Azul")