Thanks guys. Something really
strange going on.
I typed in the url
mysite.com/forum/YaBBImages/pm_on.gif and it returned the old image! I used WS_FTP to delete the file on the server and upload the updated one from my local drive.
I refresh the browser and it retains the old one! I delete the file on the server and refresh the browser. Right - Error file not found. Then uploaded the same updated file to the server again.
I refresh the browser and the new one is returned!
Very spooky. I think the images must have been cached by my ISP or something. Refreshing such that the files no longer existed dropped them from the ISP cache so the next retry forced it get the updated ones.
Rather long an uninspiring reply, but problem now resolved. Thanks for the help guys.
In the future I'll have to remember to delete files, hit the pages so the images are missing and hopefully update any caches I hit along the way. Ho hum.