var curPic = 0;  

function processPrevious() {
	
    if (curPic==0) 
    {
       curPic=Pictures.length - 1; 
    }
    else 
    {
      curPic--; 
    }
    document.myPicture.src=Pictures[curPic];    
}

function processNext() {

    if (curPic==Pictures.length -1) 
    {
        curPic=0;
        }
        else 
        {
	    curPic++; 
		}
    document.myPicture.src=Pictures[curPic];    
}