pygame.error: File is not a Windows BMP file？？？？？？？

Traceback (most recent call last): File "deep_q_network.py", line 8, in import wrapped_flappy_bird as game File "game/wrapped_flappy_bird.py", line 19, in IMAGES, SOUNDS, HITMASKS = flappy_bird_utils.load() File "game/flappy_bird_utils.py", line 21, in load pygame.image.load('assets/sprites/0.png').convert_alpha(), pygame.error: File is not a Windows BMP file