Untitled

<html>
<script type="text/javascript">
var myImages1 = new Array();
    myImages1[1] = "Zad 1.jpg";
    myImages1[2] = "Zad 2.jpg";
    myImages1[3] = "Zad 3.jpg";
//var rnd = 8;

function randomImg1() {

 rnd = Math.floor(Math.random() * myImages1.length);
    if (rnd == 0) {
            rnd = 1;
    }
    document.write('<img class="who" src="' + myImages1[rnd] + '">');
}

function showAnswer() {
    document.write('<img src="' + 'answer_' + myImages1[rnd] + '">');
}
</script>

<body>
<button onClick="showAnswer();">Show answer</button>
<script> randomImg1(); </script>
</body>
</html>