background position needs 2 properties
Code:
background-position: center top;
I prefer the shorthand. You also need to define measurements.... you simply have 9 or 777. What are those? pixels? ems? picas? points? inches?
Code:
div#image3 {
display: block;
height: 9px;
width: 777px;
background: url('images/image3.png') no-repeat center top;
}