screen.clj

(import 
  '(java.awt Rectangle Dimension Robot Toolkit)
  '(java.awt.image BufferedImage)
  '(java.io File IOException)
  '(javax.imageio ImageIO))

(defn take-screenshot []
  (let [screen (.getScreenSize (Toolkit/getDefaultToolkit)) 
        rt (new Robot)
        img (.createScreenCapture rt (new Rectangle (int (.getWidth screen)) (int (.getHeight screen))))]
    (ImageIO/write img "jpg" (new File (str (System/currentTimeMillis) ".jpg")))))

(take-screenshot)