Although in the sources it is described as the image of St. Gregory, the painting most likely depicts St. Jerome. It was created in the second half of the 18th century and corresponds to a depiction from the opposite altar.
Agata Felczyńska , "St. Jerome", [in:] "The Sacred Lesser Poland Heritage", 2025, source: https://sdm.upjp2.edu.pl/en/works/st-jerome