Change the layout of Search Box without custom delegate control
By Anatoly Mironov
The surest way to customize Search box in Sharepoint is to create a delegate control. In Sharepoint.Stackexchange there are many links to resources about this. But if you don’t have access to server or can’t deploy, the easiest way to do it is to style it with css. Thanks Steve Ottenad.
.s4-search .ms-sbgo a {
background:url(../images/search\_btn.png) no-repeat;
width:27px;
height:22px;
display:block;
}
.s4-search .srch-gosearchimg, .s4-search .ms-sbgo span {
display:none;
}
First we hide the the default image and then we add our image for search button as background.