In Photobucket just open the picture. You will see four sharing links off to the side. Click in the bottom box for "IMG". Just left click and the box should say "copied". Then right click and paste here. No fuss, no muss.
Should look like this (minus the spaces I put inside the brackets so the photo doesn't show)
[ IMG ]http://i427.photobucket.com/albums/pp354/grreatdog/TommyYoakum.jpg[ /IMG ]
Photobucket also might add some url codes in brackets. If so, just delete those until you have just the link inside the [ img ] codes. But it should work just like you paste it.