I quote that fount of uncontested truth, Wikipedia, when I say "the Kalahari Bushmen, San, Sho, Basarwa, Kung, or Khwe are indigenous people of southern Africa that spans most areas of South Africa, Zimbabwe, Lesotho, Mozambique, Swaziland, Botswana, Namibia, and Angola."
You'll notice that list of countries does not include the Democratic Republic of the Congo, which used to be the Belgian Congo, the setting for Joseph Conrad's famous Heart of Darkness.
So it's odd that two different publishers (Hesperus and Oneworld) should decide to use Kalahari Bushmen on their Heart of Darkness covers.
These are the original photos, both of men in traditional head-dresses, and both by Art Wolfe, whose website is chock-full of amazing photographs.
And here they are with the covers, just for the hell of it.
It's a bit of a shame that two publishers who do a lot to bring much great world literature into English seem to have plumped for an any-old-African-will-do approach for their covers.