Автоматический кроп лишнего фона на фото?

from PIL import Image
import math
import sys

way = '1.png'
print sys.argv[1]
way = sys.argv[1]
image = Image.open(way)
width = image.size[0]
height = image.size[1]

alpha = image.getpixel((2,2))



left = width
right = 0
top = height
bottom = 0
print str(alpha)
for x in range(width):
    for y in range(height):
        rng = math.sqrt(math.pow(image.getpixel((x,y))[0]-alpha[0],2)+math.pow(image.getpixel((x,y))[1]-alpha[1],2)+math.pow(image.getpixel((x,y))[2]-alpha[2],2))
        #print str(rng)
        if rng > 89:
            
            
            if x<left:
                left = x
            if x>right:
                right = x
            if y<top:
                top = y
            if y>bottom:
                bottom = y
print str(left)+ ','+str(top)+'   '+str(right)+','+str(bottom)                

width = right-left
height = bottom-top
img = Image.new("RGBA", (width,height), (0,0,0,0))
for x in range(width):
    for y in range(height):
        img.putpixel((x,y),image.getpixel((x+left,y+top)))


img.save("crop_"+str(way), "PNG")

print "Done!"