From what I recall, you have to first open an account with Photobucket or another website like that (it's free) then you upload to them, and then once they are there you copy the code number.
It took me several goes to copy the right code underneath the photo (choice of about 3!) but I got there eventually. If I can do it, you can but it requries patience
There's a really good step by step guide somewhere on here (possibly in Picture Gallery).