It's a simple copy/paste using Photobucket. When you're on the main PB page (with the thumbnails), look directly under the pic you want to post. You'll see part of a url (i.e.
http://www.photobucket.com/DDnekkidstripper). Left click on that and it should highlight. (You won't see the entire url but it will ALL highlight. Trust me.) Right click on that and select "Copy". Go back to your post, select where you want the pic then right click and choose "Paste". The entire url will show up and when you post your reply, the pic will show up (instead of the url). You don't have to add any tags, etc.