python script to help fix the RGB values of transparent pixels in images

replace_transparent_pixels.py

#!/usr/bin/env python

# pip install Pillow
from PIL import Image

def replace_transparent_pixels(base_image_path, replacement_image_path, output_image_path):
    base_image = Image.open(base_image_path)
    replacement_image = Image.open(replacement_image_path)

    base_image = base_image.convert("RGBA")
    replacement_image = replacement_image.convert("RGBA")

    base_data = base_image.getdata()
    replacement_data = replacement_image.getdata()

    result_image = Image.new("RGBA", base_image.size)

    # loop through every pixel in base image, and replace the RGB of the pixel with RGB from same coordinates in replacement image if the pixel in base image is transparent
    for index, pixel in enumerate(base_data):
        xy = (index % base_image.size[0], index // base_image.size[0])
        data = pixel
        if pixel[3] == 0:
            data = replacement_data[index][:3] + (0,)
        result_image.putpixel(xy, data)

    result_image.save(output_image_path)

def replace_transparent_pixels_RGB(base_image_path, rgb_value, output_image_path):
    base_image = Image.open(base_image_path)

    base_image = base_image.convert("RGBA")

    base_data = base_image.getdata()

    result_image = Image.new("RGBA", base_image.size)

    # loop through every pixel in base image, and replace the RGB of the pixel with RGB value if the pixel in base image is fully transparent
    for index, pixel in enumerate(base_data):
        xy = (index % base_image.size[0], index // base_image.size[0])
        data = pixel
        if pixel[3] == 0:
            data = tuple(rgb_value) + (0,)
        result_image.putpixel(xy, data)

    result_image.save(output_image_path)

def reveal_transparent_pixels(base_image_path, output_image_path):
    base_image = Image.open(base_image_path)
    base_image = base_image.convert("RGB")
    base_image.save(output_image_path)

if __name__ == "__main__":
    # accept arguments for base image path, replacement image path or RGB value, and output image path
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument("base_image_path", help="path to base image")
    parser.add_argument("output_image_path", help="path to output image")
    parser.add_argument("-r", "--rgb", nargs=3, type=int, help="RGB value to replace transparent pixels with")
    parser.add_argument("-i", "--replacement_image_path", help="path to replacement image")
    parser.add_argument("-v", "--reveal", action="store_true", help="reveal transparent pixels in base image")
    args = parser.parse_args()

    # if RGB value is provided, use that to replace transparent pixels
    if args.rgb:
        replace_transparent_pixels_RGB(args.base_image_path, args.rgb, args.output_image_path)
    # if replacement image path is provided, use that to replace transparent pixels
    elif args.replacement_image_path:
        replace_transparent_pixels(args.base_image_path, args.replacement_image_path, args.output_image_path)
    elif args.reveal:
        reveal_transparent_pixels(args.base_image_path, args.output_image_path)
    # if neither is provided, print error message
    else:
        print("Error: either RGB value or replacement image path must be provided")