var image = new Array();

image[0] = "media/q1.jpg"; 
image[1] = "media/q2.jpg";
image[2] = "media/q3.jpg";
image[3] = "media/q4.jpg"; 
image[4] = "media/q5.jpg";
image[5] = "media/q6.jpg";
image[6] = "media/q7.jpg"; 
image[7] = "media/q8.jpg";
image[8] = "media/q9.jpg";

function ShowQues() {
var number = image.length;
var increment = Math.floor(Math.random() * number);
var strTemp ='<img src="' + image[increment] + '" border="0">';
document.write(strTemp);
}