Hmm, that's weird.
Sometimes I see your avatar, sometimes I don't.
My first guess is that Geocities is blocking access to your picture. Geocities, for its free server, only permits a certain number of hits per time period (I don't remember if it's day or month, or what), after which they don't allow access to the image until after the time period is over. (Had this problem with an eBay pic once). My suggestion, if your school or ISP has a server you can upload to, use that.
FYI, if you post questions like this in the Lounge, a wider variety of people will read it and likely respond.
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