Remove picture borders

Unless you provide a link to a page demonstrating the problem, no one will be able to offer much in the way of assistance.

style.css of your theme; these styles:

.alignright{background-color:#EAEAEA;float:right;padding:5px;}

.alignleft{background-color:#EAEAEA;float:left;padding:5px;}

they add a pading a background color, which makes it look like a border;

removing at least background-color:#EAEAEA; from both styles should fix your problem.