var randomImage= new Array 
randomImage[0]="Geotechnical/1.jpg"; 
randomImage[1]="Geotechnical/2.jpg"; 
randomImage[2]="Geotechnical/3.jpg"; 
randomImage[3]="Geotechnical/4.jpg"; 
RandomImage[4]="Geotechnical/5.jpg"; 
RandomImage[5]="Geotechnical/6.jpg";