HTML is not sufficiently expressive language to make this code. For this you will need CSS. Make the following files:
-test.html
HTML Code:
<html>
<head>
<title>My resizable background test page!</title>
<link rel="stylesheet" type="text/css" href="styles.css">
</head>
<body>
<div id="content">
<h1>Hello world!</h1>
</div>
<img id="imgBackground" src="background.gif">
</body>
</html>
-background.gif
-styles.css
HTML Code:
#content {
position: absolute;
z-index: 5;
}
#imgBackground {
position: absolute;
z-index: 1;
width: 100%;
}
Field id = "content" contain all html code at the page itself. To be able to put picture as background use z-index. Image accordingly receive lower z-index compared to the field code. It remains only to make the picture 100% of the width of the body element.