title: How to open an image with alpha channels in OpenCV-Python?
body: <p>I'm trying to set certain pixels to be transparent on an image with the python3 cv2 library. How do I open an image so that it can support transparency?</p>
  
  <p>I looked into this and I can't find good documentation on using transparent pixels. </p>
  
  <p>The current way I'm opening images is the following:</p>
  
  <p><code>img = cv2.resize(cv2.imread("car.jpeg", cv2.COLOR_B), (0, 0), fx=0.2, fy=0.2)</code></p>
  
  <p>and I'm setting colors like this:</p>
  
  <p><code>img.itemset((r, c, 1), val)</code></p>
  
  <p>How do I edit the alpha channels?</p>