Having your Photobucket username in the image link is fine as long as the link itself can't be seen without someone actually looking for it. As for removing the hyperlink back, it depends on how you posted the image. I suggest that when you always pull the direct link from Photobucket and use our IMG tags. That way, you come out with:
[IMG]http://www....com/[/IMG]
If you were to use the IMG tag link from Photobucket, you would get this instead.
[Url=http://...][IMG]http://www....com/[/IMG][/URL]
If you used the direct link with the [SHOT] tags though, it was entirely meant to leave a hyperlink. It's a direct link to the image though, not back to your Photobucket profile, so it is okay to use.