Best to just "upload" images instead of "linking" to them elsewhere for the purpose of embedding the image into a message post. I've seen a lot of message posts look silly at other websites, blogs, forums when the image that was linked too wasn't available any more.
Worst, if the message post is old and the person that posted it is still actively posting...he/she doesn't know that old image that was linked too is no longer available.
wrbtrader