A friend (who usually knows what he's talking about) has just posted this on another forum we're both members of:
"...As of this morning, photobucket the picture hosting site have put a block on any links to photos stored on their site. This means that you will not be able to see any of the pictures that I have linked to. This will affect others that use the photobucket site. Pictures can be linked, but only with a paid subscription, which is somewhat higher than most hosting sites that you run yourself...."
I don't use Photobucket so have no way of checking it out, but thought I'd flag this up ...