title: how to do automatic image resizing in Python3 with PyGI?
body: <p>Although I have found partial and indirect answers to this question (see, e.g., <a href="https://stackoverflow.com/questions/4939734/automatic-image-scaling-on-resize-with-pygtk">this link</a>), I am posting this here because putting together the bits and pieces of the puzzle took me a bit of time, and I thought someone else might find my efforts of use. </p>
  
  <p>So, how to achieve a seamless resizing of images on buttons in GTK+ when the parent window is resized?</p>