Bartholomew’s work will be featured in our gallery beginning July 13, where the local artist will showcase many of her latest works! Diane Bartholomew Diane Bartholomew is the artist behind Yountville Art Studio, located in the Napa Valley. Established in 1983, her original artwork and portraits feature the Yount Mill Road longhorn herd, as well as large abstract landscapes and unique photographs of the local town scene.