How to add image header to top of page

[Connie]

your image seems to be 1260 width by 129 height, right?

and you say "your browser", you should think of "your monitor" and those of others.

So what with monitors which have bigger resolution, for example 1980 x ... ?

that's why the image should be centered with margin:auto

Webcontent is not like print-layout, it is not fixed with fixed size and fixed height etc.