We encounter any work of art first through its medium-whether painting, installation, etc.-and it is though this medium that we perceive the object as belonging to the field of art. In this article, I examine in the first part the particular combinations of medium and image in two cycles of Ivorian artist Theodore Koudougnon. Focusing on the Biennale of Dakar, I discuss in the second part the importance of the medium for the Biennale's cultural productions of contemporary African art. I argue in both examples that this combination of medium-image, and not their separation, allows to clarify the specific artistic character of works of art.