Question on using urllib

[Olivier Scalbert]

Hello all,

Sorry if this question is not 100% python related, it is also related to
http or html ...

Everything takes place in this page:
http://www.infometeo.be/klanten/KYC/campage2mega.php

With the following program, I can download the 2 small meteo images,
without any problem:

import urllib

urllib.urlretrieve("http://www.infometeo.be/wwweather/currentimage.php?icao=EBFN",
"meteo1.jpg")
urllib.urlretrieve("http://www.meteokust.be/metstatgr.php?s=zb",
"meteo2.jpg")

But I would like to download the main background picture.

By looking inside the html page, it seems it's url is:
http://www.infometeo.be/img.php?iid=1057

...
<table bgcolor="#6699FF">
<tr>
<td>
<table width="1280" height="960"
background="http://www.infometeo.be/img.php?iid=1057">
<tr>
<td align="right" valign="bottom">
...

Warning, the iid may vary depending time ...

I try to download it with python:
urllib.urlretrieve("http://www.infometeo.be/img.php?iid=1057",
"picture.jpg")
But then I receive only 2 bytes: CR LF I think.

If I use this url with my browser (firefox), I also get nothing (a blank
page).
If I go back to the main page with the firebug plugin activated, I can
change the iid directly inside the html code with firebug, and then,
even previous pictures can be displayed ...

So I am a bit lost ... Any help would be very appreciate !!

Thanks,

Olivier