At photobucket, under the "My Album" heading... You will see all the pics that you have uploaded, and under each pic you will see four options. Email & IM, Direct Link, HTML Code, and IMG Code. Under the picture that you want to post, double-click in the window directly to the right of the words "IMG Code," and the word "Copied" will appear in a yellow window with black text. The word "Copied" will appear only for a moment. Now in your post, just right-click and paste or use CTRL-V. You don't add anything to it, as the code will automatically be there. Then your picture will show up in the post.
Hope this helps.