See this post I made to Michael
http://thechipboard.davidspragg.com/index.cgi/page/1/md/read/id/1040643/sbj/let-s-try-again/

The pictures people are uploading through the built in uploader work fine providing they are enclosed within the correct tags because they are stored in the same folder as the post so the URL is 'internal' and the DNS issues dont apply.

I think we just have to wait however many hours it takes for the www to get everyone 'on the same wavelength'.
I guess there was so little activity on the other 2 boards in the first day or two I didnt pick up that there would be this problem.

When I made the DNS changes, immediately after we went live here, it said "changes will start taking effect in approx 3 hours"
So thats why no-one seemed to have any issues straight away.
Now Ive googled a bit further, I see it can take from that 3 hour point to anywhere between 36 and 72 hours to propogate to every ISP worldwide.