我在弄清楚如何在blender脚本中导出外部图像时遇到过这个问题。但我猜这不再直接与blender相关，更多的是与numpy和如何处理数组有关。Here is post about first problem.
所以问题是，当将numpy数组保存到图像时，它会失真，并且有多个相同的图像。请看下面的图片，以便更好地理解。
我们的目标是试图弄清楚如何使用blender自己的像素数据来使用numpy和python进行这项工作。因此，避免使用像PIL或cv2这样的库，这些库不包括在blender python中。

当保存数据时，所有最终大小的图像都可以正常工作。当试图合并4个较小的部分，以最终更大的图像，它没有正确导出。
我在blender中用python做了一个示例脚本来演示这个问题：

# Example script to show how to merge external images in Blender
# using numpy. In this example we use 4 images (2x2) that should
# be merged to one actual final image. 
# Regular (not cropped render borders) seems to work fine but
# how to merge cropped images properly???
#
# Usage: Just run script and it will export image named "MERGED_IMAGE"
# to root of this project folder and you'll see what's the problem.

import bpy, os
import numpy as np

ctx = bpy.context
scn = ctx.scene

print('START')

# Get all image files
def get_files_in_folder(path):
    path = bpy.path.abspath(path)
    render_files = []
    for root, dirs, files in os.walk(path):
        for file in files:
            if (file.lower().endswith(('.png', '.jpg', '.jpeg', '.tiff', '.bmp', '.gif'))):
                render_files.append(file)
    return render_files

def merge_images(image_files, image_cropped = True):

    image_pixels = []
    final_image_pixels = 0

    print(image_files)

    for file in image_files:
        if image_cropped is True:
            filepath = bpy.path.abspath('//Cropped\\' + file)
        else:
            filepath = bpy.path.abspath('//Regular\\' + file)
        loaded_pixels = bpy.data.images.load(filepath, check_existing=True).pixels
        image_pixels.append(loaded_pixels)

    np_array = np.array(image_pixels)

    # Merge images
    if image_cropped:
        final_image_pixels = np_array
        # HOW MERGE PROPERLY WHEN USING CROPPED IMAGES???
    else:
        for arr in np_array:
            final_image_pixels += arr

    # Save output image
    output_image = bpy.data.images.new('MERGED_IMAGE', alpha=True, width=256, height=256)
    output_image.file_format = 'PNG'
    output_image.alpha_mode = 'STRAIGHT'
    output_image.pixels = final_image_pixels.ravel()
    output_image.filepath_raw = bpy.path.abspath("//MERGED_IMAGE.png")
    output_image.save()   

images_cropped = get_files_in_folder("//Cropped")
images_regular = get_files_in_folder('//Regular')

# Change between these to get different example
merge_images(images_cropped)
#merge_images(images_regular, False)

print('END')

所以我猜这个问题与如何使用numpy处理图像像素数据和数组有关。
这里是zip文件中的项目文件夹，其中包含工作测试脚本示例，您可以在其中测试Blender中的工作原理。https://drive.google.com/file/d/1R4G_fubEzFWbHZMLtAAES-QsRhKyLKWb/view?usp=sharing