var imgselect=1;

function picchange(){

switch(imgselect){
case 0:
img1.src="../images/works2/mastard1.jpg";
imgselect++;
break
case 1:
img1.src="../images/works2/mastard2.jpg";
imgselect++;
break
case 2:
img1.src="../images/works2/mastard3.jpg";
imgselect++;
break
case 3:
img1.src="../images/works2/mastard4.jpg";
imgselect=0;
break
}
}// JavaScript Document