def load_image(name, colorkey=None):
    fullname = os.path.join('data', name)
    try:
        image = pygame.image.load(fullname)
    except pygame.error, message:
        print "Cannot load image:", name
        raise SystemExit, message
    image = image.convert()
    if colorkey is not None:
        if colorkey is -1:
            colorkey = image.get_at((0,0))
        image.set_colorkey(colorkey, RLEACCEL)
    return image, image.get_rect()

class Animal(pygame.sprite.Sprite):
    def __init__(self, img, cX, cY, addx, addy):
        pygame.sprite.Sprite.__init__(self)
        self.image, self.rect = load_image(img, -1)
        screen = pygame.display.get_surface()
        self.area = screen.get_rect()
        self.rect.topleft = (cX-1)*50+addx, (cY-1)*50+addy
        screen.blit(self.image, self.rect)