I just looked, I can never remember. On the screen when your in your library to the right there is a section called Links to share this photo. They you got Email&IM, Direct, HTML and IMG. If you click IMG it will say copied. Then you just come here to your post and right click and hit past and presto slamma jamma your picture is here for us to look at.
The Email and IM is for when you want to email a pic or the link to a pic so it don't take up some many cyber gremlins or megabytes or some such stuff.
While you in photo bucket you need to find the place where you keep your bucket private or when you post your picture everyone can look at all your other pictures. Don't recollect exactly how ya do that. Have to look around again, it's a one time deal to figure out.