Roberto Arosemena

I agree that is not the best solution but negative margins are not a hack check this article http://coding.smashingmagazine.com/2009/07/27/the-definitive-guide-to-using-negative-margins/

doing
margin-top: -5px;
on the .caption class also fixes the problem, but it was originated because of combining an inline and a block element in the same scope