Réponse:
The Lincoln monument helps convey the political subject matter and the Washington DC setting.
The women's knuckles are bloody, as if she has been punching people -- helping the image tie in with the "exact his revenge" bit.
The upside-down US flag perhaps suggests the show is set at a time of crisis (upside-down flag is a sign for distress at sea, as troubled boats turn their flags upside-down) -- or perhaps that the women's character is using her position in US government toward twisted ends.
