Kivy Image Widget On Scatter Layout: How Do I Increase Image Size?

I want to use Kivy to rotate an image of a 45RPM record. I discovered that this can be done using an image widget on a scatter layout. However I can't seem to find the code to make the image of the 45RPM record be resized to match the size of the window. I've tried for hours different iterations of code and I've become quite frustrated. Full code below with link to image.

Any Suggestions?

Appreciated In Advance.

....brad....

Image for code at: https://drive.google.com/open?id=0B-T2cvsAoZ2vQ2hmaHM0SnlQVlU

# Modified from https://gist.github.com/tshirtman/6222891
from kivy.app import App
from kivy.properties import NumericProperty
from kivy.lang import Builder
from kivy.clock import Clock

kv = """
BoxLayout:
    Widget:
        Scatter:
            center: self.parent.center
            do_rotation: False
            do_translation: False
            do_scale: False
            rotation: app.angle
            Image:
                source: '45rpm.png'             
"""
class RotateRecordApp(App):
    angle = NumericProperty(0)
    def build(self):
        Clock.schedule_interval(self.update_angle, 0)
        return Builder.load_string(kv)

    def update_angle(self, dt, *args):
        self.angle += dt * 100

if __name__ == '__main__':
    RotateRecordApp().run()