Go to the picture you want to link to on your wall :)
under the pic it says link to pic, click there then copy the code on the left. Then go to MY under the fubar logo and select settings then click about me and interests . Click in the about me section then right click and select paste. You will need to remove the tn_ part of the code so the pic is big. then click save and you're done.
If you want your about me section to show instead of the pics on your wall, you'll need to go to MY<PHOTOS>CUSTOMIZE PROFILE PHOTOS< then click and drag each photo out of the area on the right over to the box on the left and click save :)
If you want to send it to peoples SB you just copy the URL in the browser bar