title: Flood fill a shape in a binary image
body: <p>I have a binary image (see below) and I would like to mark all the points inside the central big spot as 1 (white). If I understood correctly, the best way to do it is to use a flood fill algorithm; is there any Python module you suggest to use? If not, how would you structure the script?</p>
  
  <p>Thanks!</p>
  
  <p><img src="https://i.stack.imgur.com/ITINC.png" alt="The image I am working with"></p>