Writting a file with multiple images in a grid

Question

I'm trying to write a file with multiple images (100) in a 10x10 grid. I use 3 for iterations to:

-open the file -set coordinates (i,j)

The problem is when I look my file, all I can see is the last image multiple times. Maybe the files is overwrite every time that the program enters the for loop. Until now I can't find a solution.

The code is:

    import Image

    from os import listdir
    from os.path import isfile, join
    files = [ f for f in listdir("/mnt/hgfs/Documents/Notebooks/test1/") if isfile(join("/mnt/hgfs/Documents/Notebooks/test1/", f)) ]

    new_im = Image.new('RGB', (3000,3000))

    for i in xrange(0,3000,300):
        for j in xrange(0,3000,300):
            for ima in files:
                #paste the image at location i,j:
                im = Image.open(ima)
                im.thumbnail((300,300))
                new_im.paste(im, (i,j))

    new_im.save("hola.png")

Thanks!

Answer 1

Here's a simple bug fix. You only need two for loops, not three.

import Image

from os import listdir
from os.path import isfile, join
files = [ f for f in listdir("/mnt/hgfs/Documents/Notebooks/test1/") if isfile(join("/mnt/hgfs/Documents/Notebooks/test1/", f)) ]

new_im = Image.new('RGB', (3000,3000))

index = 0
for i in xrange(0,3000,300):
    for j in xrange(0,3000,300):
        im = Image.open(files[index])
        im.thumbnail((300,300))
        new_im.paste(im, (i,j))
        index += 1

new_im.save("hola.png")

Answer 2

This is the Python 3 code to make a squre grid of images file from any directory with images using matplotlib. Square size calculates dynamicly by count of existing images.

import math
import os
import matplotlib.pyplot as plt

# Config:
images_dir = './your_dir_with_images'
result_grid_filename = './grid.jpg'
result_figsize_resolution = 40 # 1 = 100px

images_list = os.listdir(images_dir)
images_count = len(images_list)
print('Images: ', images_list)
print('Images count: ', images_count)

# Calculate the grid size:
grid_size = math.ceil(math.sqrt(images_count))

# Create plt plot:
fig, axes = plt.subplots(grid_size, grid_size, figsize=(result_figsize_resolution, result_figsize_resolution))

current_file_number = 0
for image_filename in images_list:
    x_position = current_file_number % grid_size
    y_position = current_file_number // grid_size

    plt_image = plt.imread(images_dir + '/' + images_list[current_file_number])
    axes[x_position, y_position].imshow(plt_image)
    print((current_file_number + 1), '/', images_count, ': ', image_filename)

    current_file_number += 1

plt.subplots_adjust(left=0.0, right=1.0, bottom=0.0, top=1.0)
plt.savefig(result_grid_filename)

Images in the directory screenshot

result grid image file