table.tablesorter .header {
	background-image: url(bg.png);
	background-repeat: no-repeat;
	background-size:auto 15px;
	background-position:center right;
}
table.tablesorter .headerSortUp {
	background-image: url(asc.png);
	background-repeat: no-repeat;
}
table.tablesorter .headerSortDown {
	background-image: url(desc.png);
	background-repeat: no-repeat;
}