Untitled

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Testy</title>
<style type="text/css">
    .box{
        color: #000000;
        padding: 0px;
        display: none;
        margin-top: 0px;
        background-color: #ffffff;
        text-align: center;
    }

</style>
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
    $("select").change(function(){
        $(this).find("option:selected").each(function(){
            var optionValue = $(this).attr("value");
            if(optionValue){
                $(".box").not("." + optionValue).hide();
                $("." + optionValue).show();
            } else{
                $(".box").hide();
            }
        });
    }).change();
});
</script>
</head>
<body>
    <div>
        <select>
            <option>Wybierz substancje</option>
            <option value="1">LSD</option>
        </select>
    </div>
    <div class="1 box">
        <a href="http://sin.org.pl" target="_blank">
            <img src="https://s14.postimg.org/s15q8k3u9/Untitled-1.jpg" />
        </a>
    </div>
</body>
</html>