The Sun-Maid girl was an actual person, was Lorraine Collett Petersen. In May 1915, she was discovered drying her black hair curls in the sunny backyard of her parents' home in Fresno, Calif. She was then asked to pose for a painting while holding a basket tray of fresh grapes. She appeared on a package of raisins in 1916.
Lorraine was given the watercolor in 1915 and she kept the painting and her mother's original red sunbonnet in her Fresno home until 1974 when she presented both to Sun-Maid. She passed away in 1983 but the painting is now in a vault at Sun-Maid's Kingsburg, Calif. headquarters and the sunbonnet was donated to the Smithsonian. Here is the design from 1925 and today. (Sun-Maid)