William Turner painted his Slavers throwing overboard the dead and dying in 1840, just after the official abolition of slavery in the British empire.
From Dutch VARA TV Magazine #48, 2007, about Simon Schama´s Power of Art:
We see a slave ship somewhere on an ocean, in the eye of a storm. Dying and dead slaves are seen being thrown overboard. Because this ´merchandise´ did no longer have any commercial value, slave traders in this way could reclaim lost profits from insurance companies for ´drowning´.
The painting was criticized for various reasons. … The upper class did not want to be reminded of the inhuman slave trade and they also found Turner´s use of colours too subjective.
TONY BENN ON SLAVERY, RELIGION AND JUSTICE: here.
Remembering Slavery [in the USA] Eds. Ira Berlin, Marc Favreau & Steven F Miller; book review here.