What I believe is going on here, is that Tripod is filtering incoming image requests and determining whether they are being linked in from another site, in which case they only return their little ad image. They don't want people using their site as a photo storehouse for other websites. The idea is to keep traffic moving to their site so they can feed you advertisements.
For those techies interested....
A few things things I found while testing.
1. If I right click on the tripod logo image, hit properties and copy the URL into the address line, then I would get the image.
2. If I copied the HTML source (View --> Source) of this page into a local file and named it [something].html. Then when I opened the local file in the browser I would see the picture.
3. If I then placed atHTML file on my remote webserver and called the page.... no luck. I just get the tripod logo.
It stinks but I see where they are coming from.