How to extract image content in PyQt WebKit

I am writing a image scraper using Pycurl by sending forged requests which is the same with the results by the http analyzer to the website server. Using the http analyzer

This site requires several steps of interaction to finally response with image contents. First I have to open the link by pycurl and get the gzip format response which including the html content. The request for image is then send by the site's javascript code.The server g开发者_开发问答enerated the image by a dll according to the reqeust.

I can already get the images by identifying the response content. However I found it very trivial that I have to change my code every time the website change the querying steps so I want to interact with this website by PyQt4.WebKit as a browser.

How to extract the specific image content in PyQt4.WebKit?