I have the same experience as Jeff. Getting pictures from Flickr to load on various web sites or even within email can be a real pain. I always have to figure out which format to use and then edit a bunch of junk out of the code Flickr provides.
If you simply copy/paste I think it's going to try to copy the photo itself, which you can't just paste into most web sites. You have to paste the link to the photo, not the photo itself.