[Big Dude]

Maybe the site you are tying to get the pic from dosen't allow remote linking? If thats the case save the pic to a file on your PC then upload it to a image hoasting site like www.boomspeed.com or www.imagestation.com or something like that, then do as Chara said:

1) Right click the image you want and go to properties
2) Copy the URL
3) Go to Your CP-> Edit Profile
4) Type [img] in the signature box
5) Paste the link you copied
6) Type [/img]
7) Make sure there are no spaces.

If you dont know how to copy the link you have to highlight the text you want then press "Ctrl C" or right click and go to copy.

It should look something like this: [*img*]https://www....[*/img*]
but remove the *'s for it to work.