Slave traders transport slaves to the coast of Africa. Date unknown. What is the historical context of this image

The slave trade flourished especially in West Africa/region of Sub-Sahara Africa. These course of events started in the 15 century and became more popular along the way, until reaching its peak during the 17th century. before the exploiting of Africans, we must understand why them? Before the 15th century there was still slavery but the slaves were white Slovakians or Muslims captured by European christen nations. Though when Columbus reached the New World(Americas). Then Spain started conquering the land from the American civilizations, Azteks, Mayans, and the Incans were colonized by the Spanish conquistadors. Disease spread from the whiteness's cattle that they brought killing 90% of the total American population. These disease were effective because of the Americans lack of immunity. While this happened the Spanish built huge cash crop plantations such as sugar and tobacco. Due to a low populations, there was not enough workers. So the Spanish established a Trans Atlantic Slave deal with the tribes and many city states of Africa. So the African leaders would allow the Whiteman to gather the slaves they needed from there people, mostly young African men in exchange for wealth. It is important to note that although the West African city states were first happy later on because of the shortage of young healthy men, there society fell. This picture that shows the Africans being carried to the shores of Africa, where they will be taken onboard a slave ship where its destination is unmown to the salves. 10% to 20% of slaves died during the trip because of a lack of nutrient,  starvation, and dehydration. Where ever these African men went may it be a American Plantation or the shores of Britain, they would have been auctioned off to there white slave owners in a society that is systematically racist.