Throughout the streets of New Orleans, you’re likely to stumble upon hand-painted signs made by the prolific local artist known as Dr. Bob. In the Bywater district, known today as one of the most colorful, creative neighborhoods in the city, it all comes together in a technicolor gallery space. Since the 1990s, Dr. Bob has been making art out of his Bywater studio as a response to the changing neighborhood, often returning to his famous mantra of “Be Nice or Leave.” Other signs in his gallery contain variations of it (“Be…