demo.py

import re
import urllib2
import time

max_page = 1
sleep = 1
dict_ = {}
for i in range(0,max_page+1):
    time.sleep(sleep)
    response = urllib2.urlopen('http://v2ex.com/go/afterdark?p='+str(max_page))
    for link in re.findall('href="/t/.*?"',response.read()):
        time.sleep(sleep)
        response0 = urllib2.urlopen('http://v2ex.com'+link[6:-1]).read()
        for p_url in re.findall('(http://ww[0-9]\.sinaimg\.cn/.*?/.*?\.(jpg|png|gif))',response0):
            if p_url[0] not in dict_:
                print p_url[0]
                dict_[p_url[0]] = ''
        for p_url in re.findall('(http://i\.imgur\.com/.*?\.(jpg|png|gif))',response0):
            if p_url[0] not in dict_:
                print p_url[0]
                dict_[p_url[0]] = ''