Hjælp med height: auto; i background.

* { margin: 0; padding: 0; font-family:tahoma; height: 100%; }
body { background: white; }
a { text-decoration: none; color: black; }

#site { width: 1000px; margin-left: auto; margin-right: auto; height: auto; background: #A7A7A7;}

#login_area { width: 1000px; height: 27px; background: url("../images/login_bg.png"); }

#logo_area { width: 1000px; height: 155px; background: url("../images/logo.png"); }

#menu_area { width: 1000px; height: 27px; background: url("../images/menu_bg.png"); }
#menu { width: 922px; height: 28px; float: left; background: url("images/menu.jpg"); }
#menu_punkt { font-family: Candara; color: White; margin: 5px 0 0 10px; float: left; font-size: 15px; font-weight: bold;}
#menu_split { float: left; margin: 0 0 0 10px;}
#menu_shadow { width: 1000px; height: 22px; background: url("../images/menu_shadow.png"); }

#content_left { width: 196px; height: auto; float: left; }
#content_center { width: 602px; height: auto; float: left; }
#content_right { width: 196px; height: auto; float: left; }

#box_top { width: 183px; height: 17px; background: url("../images/box_top.png"); margin: 20px 0 0 8px; font-size: 12px; padding: 3px 0 0 5px; font-weight: bold;}
#box_line { width: 178px; height: auto; background: url("../images/box_line.png"); margin: 0 0 0 8px; font-size: 12px; padding: 5px;}
#box_buttom { width: 188px; height: 1px; background: url("../images/box_buttom.png"); margin: 0 0 0 8px; }

#content_top { width: 591px; height: 17px; background: url("../images/content_top.png"); margin: 20px 0 0 8px; font-size: 12px; padding: 3px 0 0 5px; font-weight: bold;}
#content_line { width: 598px; min-height: 200px; height: auto; background: url("../images/content_line.png"); margin: 0 0 0 7px; }
#content_buttom { width: 596px; height: 1px; background: url("../images/box_buttom.png"); margin: 0 0 0 8px; }

#field {border:1px solid #535353;width:127px;height:21px;background:#ffffff;font-size:11px;font-family:tahoma; float: left; margin: 4px 0 0 2px; float: left; background:url("../images/login_input.png") no-repeat right top; border: 0; padding: 0 5px 0 10px; }
#login_button {background:url("../images/login_submit.png") no-repeat;border:0;width:27px;height:21px; margin: 5px 0 0 5px; float: left;}