Maybe you should try to link it from an image-sharing site like Imgur or Gyazo instead of the Grepolis forum. Most Inno-forums don't show you anything unless you log in on them, it could be why the image doesn't show up.
All I see is a message in French saying I have to log in.
Why don't you just change your avatar here to that one we can't see?
We know what your current one looks like.
Nope and when i rightclick the icon and choose "show graphic" i get directed to the login page from the french grepolis forum, so like Lord Jirre said upload it somewhere else and link it from there.