<?
    if ($doorcolor==blue) {
        echo '<img src="bluedoor.jpg">';
    }

    if ($doorcolor==red) {
        echo '<img src="reddoor.jpg">';
    }
    
    if ($doorcolor==green) {
        echo '<img src="greendoor.jpg">';
    }

    if ($doorcolor==purple) {
        echo '<img src="purpledoor.jpg">';
    }

    if ($doorcolor==yellow) {
        echo '<img src="yellowdoor.jpg">';
    }
?>