'Creates a course image in contentstore.'

def _create_course_image(self, course, image_name):

    image = Image.new('RGB', (800, 400), 'blue')
    image_buff = StringIO()
    image.save(image_buff, format='PNG')
    image_buff.seek(0)
    course_image_asset_key = StaticContent.compute_location(course.id, course.course_image)
    course_image_content = StaticContent(course_image_asset_key, image_name, 'image/png', image_buff)
    contentstore().save(course_image_content)
