I don't know... black levels look better the other way!
Less bandwidth your way?!
Also, since this thread has been stickied, and it was mentioned in another thread, post split - when posting the image location, the last part of the address should be the file type - .jpg or whatever the case may be. Any text after the file type may
render the link inoperable (sites like Flickr sometimes throw in extra letters/numbers with the thumbnail views - thumbnails are essentially them opening a small window to the file location, which is kinda like what you're trying to do when you post a picture here. Opening a window to their window doesn't always work).
...not that there's anything wrong with that.