How To Random Crop (Specific Area And Specific Probability) Rectangle From Image

This is my now code (it could crop image to 25 piece jpg from one image)

# -*- coding:utf-8 -*-
from PIL import Image

def cut(id,vx,vy):
    # 打開圖片(open image)
    name1 = "C:\\Users\\admin\\Desktop\\normal_random_crop\\test.png"
    name2 = "C:\\Users\\admin\\Desktop\\normal_random_crop\\test_" + id + "_crop.jpg"
    im =Image.open(name1)
    #偏移量(offset)
    dx = 100
    dy = 100
    n = 1
    #左上角切割(Left Top Poit)
    x1 = 0
    y1 = 0
    x2 = vx
    y2 = vy
    #縱向(Vertical)
    while x2 <= 512:
        #橫向切(Horizontal)
        while y2 <= 512:
            name3 = name2 + str(n) + ".jpg"
            im2 = im.crop((y1, x1, y2, x2))
            im2.save(name3)
            y1 = y1 + dy
            y2 = y1 + vy
            n = n + 1
        x1 = x1 + dx
        x2 = x1 + vx
        y1 = 0
        y2 = vy
    return n-1

if __name__=="__main__":
    id = "1"
    #切割圖片的面積 vx,vy (Crop Area)
    res = cut(id,100,100)
    print(res)

i hope to make generate amount random crop and specific every area specific probability for example : random crop 100 piece (from 512x512 image) total 104%

(

=====1%+2%+1%=====

1%+10%+10%+10%+1%+

1%+10%+10%+10%+1%+

1%+10%+10%+10%+1%+

=====1%+2%+1%=====

)

yellow area delete(don't need)