I have no idea why that happens as it hasn't got a Whitworth thread...
However, if you bring up the website (or forum for the forum pic) and then click on 'page refresh' the new picture usually comes up...Or at least it does on my computer...Ian
email (option): ian@wright52.plus.com
Isn't it down to browser cookies ?
Regardless, if I start a thread which references a forum or website pic, I always copy it to photobucket and post it. If this isn't done, the thread soon becomes confusing as the picture will be replaced.
The best thing would be if someone without a proper job and nothing better to do, such as a website owner were to make a habit of starting a thread for each new picture he adds..the rest of us could then just jump on with comments....
Mean man 
email (option): ahum@quicknet.nl