I agree with Riviera. What's the point of the "original size" option if it gets resized after loading anyway. Everyone who watches the image has to do another click to let it display in original size, pretty annoying. It would really be cool if you could fix this.
Besides, at the moment, if you click to copy the thumbnail code to the clipboard, it's always the medium code. I have to change the code url manually from "_x" to "_o" later, for the "original size" link. But those people who watch the image still have to do that other click because of the above issue.
It would be cool to have the option to get either small, medium or original thumbnail code. Or some kind of user option, where every user can set his default: "Always get medium thumbnail codes" or "Always get original thumbnail codes".
PS: Awesome pic-host, keep it up please!