there is a how to in the newbie section.

Linking a file from the Internet

Step One: First thing to do is hit "new thread" or "post reply" depending on when/why you are posting. Next, type out the text of your thread.

Step Two: Next, go to the webpage with the photo you are looking to link, and right click the picture. A box will pop up, go all the way down and click on "properties." You should see another box pop up, highlight the address value (everything including "http" all the way to the end)and copy.

Step Three: Press Img box, paste the address of the pic you just copied and the press the Img again.

Step Four: You can preview that everything went well or you can submit to post your picture