Make thumbnails easily with opencv from the erotic video folder

import cv
import os
import sys

f = open('./Sites/a.html', 'w')

n=0
file_list=os.listdir("/Volumes/a/new/")
for file in file_list:
 capture=cv.CaptureFromFile("/Volumes/a/new/"+file)
 cv.SetCaptureProperty(capture,cv.CV_CAP_PROP_POS_FRAMES,1000)
 image=cv.QueryFrame(capture)
 cv.SaveImage("./Sites/img/"+str(n)+"_0.jpg ",image)
 capture=cv.CaptureFromFile("/Volumes/a/new/"+file)
 cv.SetCaptureProperty(capture,cv.CV_CAP_PROP_POS_FRAMES,2000)
 image=cv.QueryFrame(capture)
 cv.SaveImage("./Sites/img/"+str(n)+"_1.jpg ",image)
 capture=cv.CaptureFromFile("/Volumes/a/new/"+file)
 cv.SetCaptureProperty(capture,cv.CV_CAP_PROP_POS_FRAMES,3000)
 image=cv.QueryFrame(capture)
 cv.SaveImage("./Sites/img/"+str(n)+"_2.jpg ",image)
 capture=cv.CaptureFromFile("/Volumes/a/new/"+file)
 cv.SetCaptureProperty(capture,cv.CV_CAP_PROP_POS_FRAMES,4000)
 image=cv.QueryFrame(capture)
 cv.SaveImage("./Sites/img/"+str(n)+"_3.jpg ",image)

 f.write('<img src="./img/'+str(n)+'_0.jpg " width=200><img src="./img/'+str(n)+'_1.jpg " width=200><img src="./img/'+str(n)+'_2.jpg " width=200><img src="./img/'+str(n)+'_3.jpg " width=200><br>'+file+'<br>')
 n+=1

f.close()