Why does my avatar keep disappearing?

Simple question: Why does my avatar keep disappear?
I put a URL in, the image appears, both in my 'settings' are and on the page where I'll post a message.

It'll show the first time I put a URL in my profile for it, and post a message, then it's gone and I'll just have the annoying red 'x'.

It's most annoying.

You're linking to an image on Geocities that limits such things,
www.geocities.com...

Try uploading the image to our server using the upload feature in the board toolbar at the top.

Here put this link into yur avatar URL space.

www.abovetopsecret.com...