var Num=3;
var NumT1=1;
var NumT2=2;
var NumT3=4;
var NumT4=5;

function preloadImg() { 
	var args = preloadImg.arguments;
	document.imageArray = new Array(args.length);
	for(var i=0; i<args.length; i++) {
		document.imageArray[i] = new Image;
		document.imageArray[i].src = args[i];
	}
}

function scrollImg(Dir) {
	var Picts=document.imageArray.length/2;

	if (Dir=='next') {
		Num==Picts ? Num=1 : Num++;
		NumT1==Picts ? NumT1=1 : NumT1++;
		NumT2==Picts ? NumT2=1 : NumT2++;
		NumT3==Picts ? NumT3=1 : NumT3++;
		NumT4==Picts ? NumT4=1 : NumT4++;
	}
	
	if (Dir=='prev') {
		Num==1 ? Num=Picts : Num--;	
		NumT1==1 ? NumT1=Picts : NumT1--;	
		NumT2==1 ? NumT2=Picts : NumT2--;
		NumT3==1 ? NumT3=Picts : NumT3--;
		NumT4==1 ? NumT4=Picts : NumT4--;
	}
	
	document.getElementById('img_photo').src='images/photo'+Num+'.jpg';
	document.getElementById('t1').src='images/thumb'+NumT1+'.jpg';
	document.getElementById('t2').src='images/thumb'+NumT2+'.jpg';
	document.getElementById('t3').src='images/thumb'+NumT3+'.jpg';
	document.getElementById('t4').src='images/thumb'+NumT4+'.jpg';
}