Script strangely crashes

[t1meshift]

Don't know what's going on, I just added some pictures from Google Image Search in folder with Flickr downloads and this is what I get on output:

C:\Users\yury\Downloads\image-mosaic-master\image-mosaic-master\mosaic>python colour-mosaic.py ./cells ./i.jpg ./j.jpg
Traceback (most recent call last):
  File "colour-mosaic.py", line 52, in <module>
    "colour": average_colour(pixels)
  File "colour-mosaic.py", line 25, in average_colour
    channels = len(pixels[0, 0])
TypeError: object of type 'int' has no len()