size of an image on a button

[Christopher Backhouse <cjbackhouse gmail com>]

If I set a button to have an image like this:
  	 
gtk_button_set_image(GTK_BUTTON(button),gtk_image_new_from_file("fname.svg"));

then the button grows to the full size of the image (huge). Using:

gtk_widget_set_size_request(button,30,30);

I can make the button have a sensible size, but the image is still full 
size. How can I make the image scale with the button so it always fills it?
And do I really have to make a new GtkImage for every button? Seems like 
a waste if they are all the same.