What makes a portrait a portrait? Explore this question, among others, with M.V. Museum’s Ann DuCharme on Tuesday, March 6, at 6 pm at the Oak Bluffs library. The majority of the discussion will examine portraits of Barack and Michelle Obama. Afterward, Ms. DuCharme will take visitors through various works in the museum’s collection. For more information, visit oakbluffslibrary.org, or call 508-693-9433.