Developer Scott N. Resnick has made a quick million-dollar profit from a Greenwich Village townhouse, which he sold for $4.6 million in February after buying it for exactly $1 million less four months earlier, according to city records posted today. Resnick paid $3.6 million for the 1,620-square-foot building. The three-story townhouse at 291 West 4th Street is more than a hundred years old, and is part of the Greenwich Village Historic District. Resnick is president of the real estate firm SR Capital and was once executive managing director at his family’s firm, Jack Resnick and Sons, one of the city’s largest owners of office properties. He is a trustee of the Whitney Museum of Art and a board member of the Grand Central Partnership business improvement district.