background-position: center;.
Conseguir resolver com o código abaixo.
.btmlimpar{ background-image: url(limpar.gif)!important; background-repeat:no-repeat; [b]background-position: 10%;[/b] background-color: silver; padding-left:25px; border: 2px outset; color: black; font-family: Arial,Helvetica,sans-serif; border: 1px outset; font-size: 14px; text-align: center; height: 25px; }