[Matt]

Hot linking is like direct linking except it is linking content from someone else's Photobucket account. When content is linked from someone else's Photobucket account, it is using resources allocated to that Photobucket account.

Bandwidth usage is allocated on an individual account basis and there is a limit to the bandwidth usage allowed per month for free Photobucket accounts. If you have linked content from someone else's free Photobucket account, you take the risk of having that content on your webpage replaced with a 'Bandwidth Exceeded' icon if the allotted monthly bandwidth usage is exceeded for that account. If the account owner chooses to remove that content from their Photobucket account, the links on your webpage will break. You have no control over that account and cannot do anything to resolve the issue other than remove the link from your webpage.

From Photobucket's FAQ on hotlinking.