The doctype you are using will throw IE9 and under into quirks mode and render much like IE5 so you lose any benefits of css that was coded this century.
Your menu is 800px wide and you have added 30px left padding so its total width is 830px. In quirks mode IE9 and under use the old broken box model and padding is included in the width but other browsers add the padding to the width so there will be a 30px difference between IE and other browsers.
Use a full doctype which for html4 should be this one:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
Now all browsers will render the same and thus you need to reduce the menu width by 30px.
(As an aside you can use box-sizing to change box-models these days.)
[B]width:770px;/* do not omit the px or it will be treated as zero*/[/B]
Set the image to display:block to kill the whitespace under it as images are inline by default and placed on the baseline like text to allow room for dwescenders.
If you need images inline then add a class to the image instead and target it like that.