How to vertically concatenate hundreds of .png files in python

I have about 250 .png files in one directory.

I need to vertically concatenate them from python.

Here is the code I have so far.

list_im = []  <- this is the list of .png files <- How do I populate it if I have 250 files in one directory?
imgs    = [ Image.open(i) for i in list_im ]
# pick the image which is the smallest, and resize the others to match it (can be arbitrary image shape here)
min_shape = sorted( [(np.sum(i.size), i.size ) for i in imgs])[0][1]
imgs_comb = np.hstack([i.resize(min_shape) for i in imgs])


# for a vertical stacking it is simple: use vstack
imgs_comb = np.vstack([i.resize(min_shape) for i in imgs])
imgs_comb = Image.fromarray( imgs_comb)
imgs_comb.save('concatenatedPNGFiles.png' )

How do I populate the list_im with 250 .png files in python?

Solution

I would do something like this:

import os
from glob import glob
from PIL import Image
import numpy as np

# Get the directory path where your PNG files are stored
directory_path = "/path/to/directory/with/png/files"

# Create a list of all PNG file paths in the directory
list_im = glob(os.path.join(directory_path, "*.png"))

imgs = [Image.open(i) for i in list_im]

# pick the image which is the smallest, and resize the others to match it (can be arbitrary image shape here)
min_shape = sorted([(np.sum(i.size), i.size) for i in imgs])[0][1]
imgs_comb = np.vstack([i.resize(min_shape) for i in imgs])

imgs_comb = Image.fromarray(imgs_comb)
imgs_comb.save('concatenatedPNGFiles.png')

import os: This module provides a way to interact with the operating system, including file and directory operations.
from glob import glob: The glob function from the glob module is used to find all pathnames matching a specified pattern (in this case, *.png).
directory_path = "/path/to/directory/with/png/files": Replace this with the actual path to the directory containing your PNG files.
list_im = glob(os.path.join(directory_path, ".png"))* : This line creates a list of all PNG file paths in the specified directory using glob. The os.path.join function is used to join the directory path and the pattern (*.png) to create a valid path.

With this modification, the list_im will contain all the PNG file paths in the specified directory, and the rest of your code should work as intended.