如何在pygame中将png图片上传为精灵，而不是黑色背景？

import pygame

pygame.init()
width, height = 800, 600
screen = pygame.display.set_mode((width, height))

image = pygame.image.load("image.png").convert_alpha()

sprite = pygame.sprite.Sprite()
sprite.image = image

sprite.rect = sprite.image.get_rect()
sprite.rect.center = (width // 2, height // 2)

sprite_group = pygame.sprite.Group()
sprite_group.add(sprite)

running = True
while running:
    screen.fill((0, 0, 0))  # 清空屏幕
    sprite_group.draw(screen)  # 绘制精灵组中的精灵对象
    pygame.display.flip()  # 更新屏幕显示