How to display a picture from an array - arrays

Question

In order to manipulate images later by swapping pixels ("photobooth transformation"), I started by writing a script to create an array of dimension n x n , from a "photo. png" of n x n pixels. But when I want to check if the table is really the same as the picture, it doesn't work
Here is the script:
from PIL import Image
import numpy as np
#the image is 50x50 pixels in gray mode
im =Image.open(r "D:\0-Python0-Image pixelsphoto.png")
print("size=",im.size," ",'mode=', im.mode," ", "format=",im.format)
im.show()
# Image → numpy array
T= np.array(im)
# array formatting ..there are 50 rows like this one
for i in range(0,50):
print('{:>3d}'.format(T[u][0]),'{:>3d}'.format(T[u][1]),......'{:>3d}'.format(T[u][48]),'{:>3d}'.format(T[u][49]),end=""),print()
Then I copy the table in a text file and save it in the format "photo.pgm" :
P2
49 49
255
18 17 16 12 11 10 11 13 ........ .
19 20 17 14 13 13 13 12 ..........
etc
The script works well, but when I open the file "photo.pgm", the pixels are mixed up and I can't find the initial photo
thank you for your help

Answer 1

thank you pipo1980 for your help
but in the meantime I found an explanation to my problem
In fact in the 50x50 array the indexes are counted between 0 and 49
while in the photo application (GIMP or Photoshop) pixels are counted between 1 and 50
I made the mistake to define the pgm file with the specifications
P2 49 49 255
instead of
P2 50 50 256
So the problem is solved