That's typically because the images were taken down. A lot of people use we-todd-did-racing.org and it goes up and down on a fairly regular basis.
Also, if the posts are old, the URL is usually outdated. Take a brief trip to the member's ride forums and look a recent thread in there (mine, for example - look for my old username, andywrx). Should be lots of pics and they should all work.
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