Rectangles and Pop-Ups 300 x 250 IMU – (Medium Rectangle) 250 x 250 IMU – (Square Pop-Up) 240 x 400 IMU – (Vertical Rectangle) 336 x 280 IMU – (Large Rectangle) 180 x 150 IMU – (Rectangle) 300 x 100 IMU – (3:1 Rectangle) 720 x 300 IMU – (Pop-Under) Banners and Buttons 468 x …