Answer: It is describing the dreadful voyage of a group of enslaved Africans on a slave ship—more specifically the so-called middle passage voyage.
Explanation: Just to elaborate a little on the answer, it can be added that this is an excerpt from Olaudah Equiano's bestseller autobiography (1789). He was a former enslaved African who was eventually able to buy his freedom and become a seaman and a merchant. In this passage he is relating the horrors he experienced and witnessed during the so-called middle passage voyage across the Atlantic Ocean to the New World. He describes the unbereable voyage aboard an overcrowded ship, the unhealthy conditions, the diseases and the deaths, as well as the screams and the groans of those that, like him, were obliged to leave their homes and work as slaves.
Keeping it simple means that the reason for your photograph is clear and understandable.
