Hide coordinates in matplotlib

I am currently trying to hide the coordinates in a grid in matplotlib (see code below). Unfortunately no matter which way I try it only the bottom right position gets hidden. All other coordinates/axes are still being displayed. Would be wonderful if someone could help me with that since I do not know what else to try right now.

import matplotlib.pyplot as plt
from PIL import Image

fig,ax = plt.subplots(6,7)
plt.axis('off')

filenames=['gelb.png'.format(i) for i in range(42)]
for i in range(42):
    #plt.axis('off')
    with open(filenames[i],'rb') as f:
        image=Image.open(f)
        ax[i%6][i//6].imshow(image)
fig.show()