python+imageMagick写的一个压缩图片脚本

!/usr/bin/python
import os
import cPickle as p
import re
import Image

def imageCompre(imagedir = '.', imagelistfile="image.data"):

    datafile = imagedir+'/'+imagelistfile
    allowImageType = ['jpg','jpeg','gif','png']
    pre = re.compile('^big|^sml|^mid*');

    if os.path.isfile(datafile):
        f = file(datafile)
        imagelist = p.load(f)
        f.close()
    else:
        imagelist = []

    for item in os.listdir(imagedir):
        if item:
            if os.path.isdir(imagedir+"/"+item):
                imageCompre(imagedir+"/"+item,'image.data')
            else:
                if item.split('.')[-1] in allowImageType and item not in imagelist and not pre.match(item):
                    imagelist.append(item);
                    #convert image file
                    convertImage(imagedir,item)
    #update image.data
    if imagelist:
        f = file(datafile, 'w')
        p.dump(imagelist, f)
        f.close()
        #delete imagelist tuple
    del imagelist


def convertImage(imagedir,item):
    sourcefile = imagedir+"/"+item
    im = Image.open(sourcefile);

    if im.size[0]<=120:
        os.system("cp %s %s/big-%s -a" %(sourcefile,imagedir,item))
        os.system("cp %s %s/mid-%s -a" %(sourcefile,imagedir,item))
        os.system("cp %s %s/sml-%s -a" %(sourcefile,imagedir,item))
    else:
        if im.size[0] > 640:
            os.system("convert -resize 640 %s %s/big-%s" %(sourcefile,imagedir,item))
            os.system("convert -resize 400 %s %s/mid-%s" %(sourcefile,imagedir,item))
            os.system("convert -resize 120 %s %s/sml-%s" %(sourcefile,imagedir,item))
        elif 400 < im.size[0] <= 640:
            os.system("cp %s %s/big-%s -a" %(sourcefile,imagedir,item))
            os.system("convert -resize 400 %s %s/mid-%s" %(sourcefile,imagedir,item))
            os.system("convert -resize 120 %s %s/sml-%s" %(sourcefile,imagedir,item))
        elif 120 < im.size[0] <= 400:        
            os.system("cp %s %s/big-%s -a" %(sourcefile,imagedir,item))
            os.system("cp %s %s/mid-%s -a" %(sourcefile,imagedir,item))
            os.system("convert -resize 120 %s %s/sml-%s" %(sourcefile,imagedir,item))

#init image
dirRoot = raw_input('input images directory (default is ./)')
if len(dirRoot) == 0:
    dirRoot = '.'

if os.path.isdir(dirRoot):
    imageCompre(dirRoot);
else:
    print 'the directory %s is not exists' %dirRoot;