The Anger of Achilles is an oil-on-canvas painting of 1819 by the French artist Jacques-Louis David. One of the last of David's history paintings, it shows the moment in Greek myth when Agamemnon reveals to Achilles that he has not actually brought his daughter Iphigenia to him as a bride, but rather intends to sacrifice her in order to appease the goddess Artemis. Achilles begins to draw his sword in anger upon hearing this, while Agamemnon's wife, Clytemnestra, looks on in grief and sadness with her hand on her daughter's shoulder.
More on David: https://en.wikipedia.org/wiki/Jacques-Louis_David
Im not an art scholar, but it looks to me more like Achilles is turning away in embarrassment as Agamemnon points at his tiny penis that has saddened the women.
"Look at his big dick. So uncivilised!"