How to generate an image in Python?

I can load the image and display it as follows:

   import  cv2img = cv2.imread ( "" 1.jpg "" ) cv2.imshow ( "" Original "" , img)     
 for example, I can load any, draw a white rectangle and lifting it on top of it and lifting it. On the screen. 
  
 However, what if I want to get a white image without preliminary download? How to replace the operation of loading the generation of an object of the image?