Need help with this issue

[MagnificentCreature]

File "C:/Users/seanw/.spyder-py3/temp.py", line 42, in
label = int(filename.split('\\')[2])

ValueError: invalid literal for int() with base 10: 'im56908.png'

[wutonghhu]

I‘m not sure if i did it right. I changed [2] into [-2], and the Error disappeared.
btw，I met a issue in the last part :

gzip resulting files

for name in Names:
os.system('gzip' + name[1] + '-images-idx3-ubyte')
os.system('gzip' + name[1] + '-labels-idx1-ubyte')
the error is :
'gziptrain-images-idx3-ubyte' is not an internal or external command, nor is it a runnable program
Or batch files.

can you help me with this one?