There is no lottery visa to migrate to Cameroon. And many people are right to mock the images.
People are tempted to say that the photoshopped image is the handiwork of a patriot (while some people dream of leaving Cameroon, others want to stay and some others want to settle and work there). This is not the handiwork of a patriot, however. Indeed, this image was posted on the Facebook page of “Rumeurs d’Abidjan” in 2017.
Was the image photoshopped by Ivorians? Nobody can tell. The only thing that can be told is that instead of Cameroon's lottery visa, people can play the US lottery visa despite tougher migration measures.