title: Transparent Backgrounds on Buttons in Tkinter
body: <p>I have a <code>Button</code> with a button image but when it is in my window the background of the button clashes with the background of the window. It is a .png image but <code>tkinter</code> seems to want to keep the image as a quadrilateral by adding grey space. Is there a way to make the empty space of a button become transparent so that you are just left with the button image?</p>
  
  <p>I am using Python 3.4.2 on Windows 8.</p>