Do you need permission to make fun of listing photos on the internet?┬áThat question has real estate pros divided and may lead real estate giant Zillow Group into yet another legal battle over listing photo copyrights. This week, Zillow Group, a company whose market cap currently stands at $8.9 billion, sent a cease-and-desist letter to 23-year-old graduate student and blogger Kate Wagner demanding that that she remove photos obtained from Zillow from her popular architecture criticism blog McMansion Hell …