Post preview height and padding

Dear developer, How to decrease the padding under the post image (or height of the post container) in post container for every post on main page? I want the post container to end right under the image - without the empty space (where usually the "Posted in..." text is located. Also - how to decrease the padding above post title? Please see the image in the link below for details: http://imageshack.us/photo/my-images/132/postxi.png/ Best regards