var files=2;

with (Math) {
picset=(round (random( ) * (files-1))+1);
};

 

if (picset==1)
{ 
document.writeln (' <div id="site-visual" style="background-image:url(images/ua_small_01.jpg);"></div>  ');
}

if (picset==2)
{ 
document.writeln (' <div id="site-visual" style="background-image:url(images/ua_small_02.jpg);"></div>  ');
}