Spanish magazine puts Michelle Obama's head on a portrait of topless slave

Spanish magazine, Magazine de Fuera de Serie placed Michelle Obama's head in a 1800 portrait of a slave with an exposed breast, with an article that says - 'Michelle Granddaughter of a Slave, Lady of America'. Both Mrs Obama's great-great grandfather and great-great-great grandmother were slaves.

What do you think of this? Offensive? Racist? Artistic?