title: How to download an image straight to a bytesIO variable?
body: <p>I have an existing <code>url</code> of an image, 
  I want to download the image straight to a variable (no need to actually download it, maybe get it from a response?</p>
  
  <p>The end result will be "download an image into a <code>BytesIO()</code> variable".</p>
  
  <p>What is the correct way to do so?</p>