Image en arrière plan à partir d'une url

Help please ...
Can someone help me. I'm trying to insert image in excel 2003 background using a URL, not from file on local computer
what is the code

I Tried this unsuccessfully
====
Sub imageurl()
ActiveSheet.SetBackgroundPicture Filename:="http://www.google.com/intl/en_ALL/images/logo.gif"
End Sub
====
Thanks