As the 17th-century Neapolitan painters might have said, "No guts, no glory." They weren't satisfied unless they could work a massacre, a stabbing, a writhing death and the odd beheading into each canvas.

The 100 works in "Painting in Naples from Caravaggio to Giordano" are not for the squeamish. The sprawling show opening Sunday at the National Gallery of Art's East Building will shake up Washington art audiences accustomed to beautiful mannerist traditions and reverent religious works, like those by Raphael or the delicate portraits by 17th-century painters from the northern countries (displayed upstairs). These are reverent, too, but the accent is on realism no matter how messy.

It was Caravaggio who sparked a painting revolution by cashing in on violence. Early patrons had to overlook his police record -- he came to Naples after killing a man in Rome over a tennis match. His brutal realism, executed in short order on tall canvases, was widely copied. His was the plasmatic, bone-crunching approach. He was best known for the chiaroscuro technique, using sharp contrasts of light and shade to make figures bolt from their scenes.

In addition to five works by Caravaggio and others reflecting his influence, the show documents the patronage of religious orders, Naples at mid-century, still lifes and landscapes, painting after the Black Death and Naples in the second half of the century.

Spaniard Jusepe de Ribera was second only to Caravaggio in popularity. He was among the first to depict the lower classes on canvas with stark realism, and he broke new ground in the severed-heads department. Then again, it was Luca Giordano who actually painted flies on the open wounds of the beggars receiving alms from St. Thomas, while the still life of flowers by Giuseppe Recco contains a vase crawling with serpents, one of which bites off a man's head.

Even the sainted are seen unromantically: "St. Catherine of Alexandria" by Francesco Fracanzano is an imposing, monumental image, but she looks bored.

After the plague, which wiped out half the city including most of the greatest painters, those artists still alive produced one massacre scene after another. The largest room in the exhibition holds Giordano's "S. Gennaro Frees Naples from the Plague," the bottom half of which shows ghastly plague victims, Goya-style, while the top is dreamily Rubenesque. But the most compelling work is "The Feast of Herod" by Mattia Preti: not a pretty picture. There is a studied lack of drama in the scene, which was copied from Rubens' work of the same title. But the woman at the center is about to lose her lunch as the head of John the Baptist is presented on a platter. PAINTING IN NAPLES -- At the National Gallery of Art's East Building, opens Sunday, continuing through May 1.