Imagemagick：画像を下から垂直に分割し、最後の部分のサイズを変更します。

今これを使用してください：

#!/usr/bin/python3.9

import numpy as np

import cv2

import sys
import os
import math

import argparse
parser = argparse.ArgumentParser(description="split png image vertically from bottom")
parser.add_argument("fname", help="img file name")
parser.add_argument("prefix", help="prefix of output pngs")
parser.add_argument('--height', action='store_true', help="output img height. default 128")
parser.add_argument('--width', action='store_true', help="output img width. default 128")

args = parser.parse_args()
print(args.height)
print(args.fname)



abspath=os.path.abspath(args.fname)
absdir=os.path.dirname(abspath)

tarW = 128
if(args.width):
    tarW = args.width
tarH = 128
if(args.height):
    tarH = args.height

print(tarH)

img = cv2.imread(abspath, cv2.IMREAD_UNCHANGED)
if(img is not None):
    height=img.shape[0]
    width=img.shape[1]
    fulls=math.floor(height/tarH)
    total=math.ceil(height/tarH)
    print("fulls:" + str(fulls))
    print("total:" + str(total))

    for i in range(0,fulls):
        ty=height-((i+1)*tarH)
        tx=0
        by=ty+tarH
        bx=tarW
        iname = args.prefix + "_" + str(i) + ".png"
        print(iname + ": cropping from " + str(tx) + "x" + str(ty) + " to " + str(bx) + "x" + str(by))
        oimg=img[ty:by,tx:bx]
        cv2.imshow("asd", oimg)
        cv2.waitKey()
        cv2.imwrite(absdir + "/" + iname, oimg)


    #top rest
    lty = 0
    lby = height%tarH
    ltx = 0
    lbx = tarW
    limg1=img[lty:lby,ltx:lbx]
    iname = args.prefix + "_" + str(fulls) + ".png"

    ydiff = tarH - lby
    print(iname + ": cropping from " + str(ltx) + "x" + str(lty) + " to " + str(lbx) + "x" + str(lby) +  ", missing " + str(ydiff) + "x" + str(tarW) + ". generating...")

    #additional transparent
    aw, ah = tarW, ydiff
    n_channels = 4
    transparent_top = np.zeros((ah, aw, n_channels), dtype=np.uint8)

    oimg = cv2.vconcat([transparent_top, limg1])

    cv2.imshow("asd", oimg)
    cv2.waitKey()
    cv2.imwrite(absdir + "/" +  iname, oimg)


else:
    print("not valid image")
    sys.exit(1)