from PIL import Image
img=Image.open('56.jpg')
pixels = img.load()
maxLoad = img.width * img.height
onePer = maxLoad / 100
k = 0
for i in range(img.width):
    for j in range(img.height):
        if(i*j>k*10*onePer):
            print("Обработано", k*10, "%" )
            k+=1
        pixels[img.width-i-1, j] = pixels[i,j]
img.show()
img.save('1.jpg')