The other day I dragged a picture from Mozilla 1.2a to my desktop, and it made a picture clipping. Just for the heck of it, I dragged the clipping back to Mozilla and it opened the original picture from the link, not the clipping.
Thinking that was odd, I opened the clipping in the Finder, and it was indeed the picture.
So I tried opening it in GraphicConverter, and it opened as a picture. But when I dropped it on TextEdit, it pasted in the original picture URL as text, instead of the picture!
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020917064154189