background image not filling window

I'm creating a pop-up with a background image from CSS as below

#gui-01-Qa {
background-image:url(path/to//file.jpg);
background-repeat: no-repeat;
background-position: top left;

}

This all works fine apart from (what looks like) a boarder of approx 5px being added. It's not coming from my co开发者_如何学Gode, but both IE and Firefox are adding it. So whet's it coming from ????

Any ideas would help Many thanks Giles

That border is most likely a padding or margin on the body element. Just add html, body { margin:0; padding:0;}, or use a CSS reset.

If you're wondering how to stretch a background image to fill the entire window regardless of resolution while preserving the aspect-ratio A List Apart recently published a very good article on the subject.

Maybe the element with your CSS ID "gui-01-Qa" is causing the border. Try to set margin and/or padding to 0.