While creating an interface, the Labels have a box (in the options tab) in which you can check, this box is named "Scale Image to Fit Control". So when ever someone resizes the whole window in runtime the image will resize to fit properly.
The Button does not have such a command, so if I were to add an image to it and later resize my window while in runtime, the image will remain the same size while the button increases in size.
So such a feature to allow a button image to fit properly, once the button size has been increased during runtime, would be quite handy.
When increased at runtime: