title: OpenCV - clean memory
body: <p>is there a way to clean the memory occupied by <code>cv2.imread</code>? I wrote a script to load and analyse a stack of images and I am having some memory leak issues, I suspect because the images are kept in storage. What I am doing now is just</p>
  
  <pre><code>im = cv2.imread('file.tif')
  [...]
  del im
  </code></pre>
  
  <p>Which doesn't seem to work. Thanks!</p>