Adding image to top of block

[deverill2010]

I am trying to add some 'notebook rings' to the top of my blocks - http://www.midwiferyonline.co.uk/forum.php?styleid=13

I have removed the block title and adjusted the padding etc and it sits perfectly on the top block.

However if I repeat the image it goes all screwey on the other blocks.

I don't quite know what I am doing wrong..

Any help please?