I use photobucket and just copy and paste the IMG tags over, posts the full photo in full res without any scaling issues or anything.
Only annoying thing is that it takes a while to sort out and if you use photobucket more generally, then it starts to take up a lot of space and you only get limited storage without paying for more.
You could try another image hosting site, I've always used imgur. Although it sounds like it could be your web browser, do you have another one you could test it with?
Ah yeah I should try different browsers, I always IE and I would've throught the image hosting websites would be better optimised for the IE browser. Definitely worth a try though. Ah ok thanks for the help too Ed, again will try when I can next
Only annoying thing is that it takes a while to sort out and if you use photobucket more generally, then it starts to take up a lot of space and you only get limited storage without paying for more.