
Abolitionists used appearances by white-looking slaves to press the cause for the slaves' freedom.
Rosina Downs, known as Rosa, was one of five children and three adults freed at the city of New Orleans by Union Major General N.P. Banks in 1863. Downs and other white-looking slave children were photographed and were taken to northern cities for appearances. The children's appearance troubled notions of racial difference and fostered an unease laced with fascination among white, northern viewers. Cartes de visite of slave Rebecca Huger, an 11-year-old who by all appearances seems white, were a reminder to people that the slave laws might at some point enslave "whites" as well. You can read more about the ways in which Rebecca and others like her were used by abolitionists to promote freedom for all
here.