#header .row_2 {
  background: transparent url(header_large.png) center center no-repeat;  
  _background:transparent url(header_large.gif) no-repeat scroll center center;
}
.page3 #header .row_2 {
  background: transparent url(header_small.png) center center no-repeat;  
  _background:transparent url(header_small.gif) no-repeat scroll center center;
}