When Mayor Michael R. Bloomberg redid Gracie Mansion in 2002, it was featured in Architectural Digest. Mayor Bill de Blasio’s redecoration was featured this week on Instagram (2,718 likes by Friday). The medium by which the reveal was made says as much about the changing of the guard as the difference in taste shown by the photographs in question. Federal end tables are out, coffee tables you can rest your feet on are in. For New York City’s first family, the move to Manhattan from Park Slope clearly felt more like an upheaval than a dream realized. The story line was less about being true to the house’s roots than being true to their own.