var randNum=Math.round((Math.random()*5)),img1,qArray=new Array(5);

qArray[0]="<img src='images/cycle/img_01a.jpg' width='300' height='130'>"
qArray[1]="<img src='images/cycle/img_01b.jpg' width='300' height='130'>"
qArray[2]="<img src='images/cycle/img_01c.jpg' width='300' height='130'>"
qArray[3]="<img src='images/cycle/img_01d.jpg' width='300' height='130'>"
qArray[4]="<img src='images/cycle/img_01e.jpg' width='300' height='130'>"
qArray[5]="<img src='images/cycle/img_01f.jpg' width='300' height='130'>"

img1=qArray[randNum];
document.write(img1);