how to adjust your background image to screen size css code example
Example 1: fill and no repeat background image css
/* with CSS 3 */
#yourdiv {
background: url('bgimage.jpg') no-repeat;
background-size: 100%;
}
Example 2: how to set background automatically with my screen height
html {
background: url(image.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}