As far as I remember, you cannot do anything from a legal standpoint unless you have an actual copyright. I sincerely doubt that anybody here wouls copyright an image, or even a whole vB style. The person might lose credibility, but you cannot sue them.
And as for MSPaint, the best example I can give is
this. Most of the layout there was made in MSPaint (I assume the banner wasn't), and the previous versions of the layout were too.