title: Python OpenCV - imshow doesn't need convert from BGR to RGB
body: <p>As I'm lead to believe, OpenCV reads images in BGR <strike>colorspace</strike> ordering and we usually have to convert it back to RGB like this:</p>
  <pre><code>img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
  </code></pre>
  <p>But when I try to simply read an image and show it, the coloring seems fine (without the need to convert BGR to RGB):</p>
  <pre><code>img_bgr = cv2.imread(image_path)
  cv2.imshow('BGR Image',img_bgr)
  img_rgb = cv2.cvtColor(img_bgr, cv2.COLOR_BGR2RGB)
  cv2.imshow('RGB Image',img_rgb )
  cv2.waitkey(0)
  </code></pre>
  <p>So is <code>imshow()</code> changing the ordering within the function automatically (from BGR to RGB) or the ordering has been BGR all along?</p>