var num=0;
imgArray = new Array();
imgArray[0] = "pics/1.jpg";
imgArray[1] = "pics/2.jpg";
imgArray[2] = "pics/3.jpg";
imgArray[3] = "pics/4.jpg";
imgArray[4] = "pics/5.jpg";
imgArray[5] = "pics/6.jpg";
imgArray[6] = "pics/7.jpg";
imgArray[7] = "pics/8.jpg";
imgArray[8] = "pics/9.jpg";
imgArray[9] = "pics/10.jpg";
imgArray[10] = "pics/11.jpg";
imgArray[11] = "pics/12.jpg";
imgArray[12] = "pics/13.jpg";
imgArray[13] = "pics/14.jpg";
imgArray[14] = "pics/15.jpg";
imgArray[15] = "pics/16.jpg";
imgArray[16] = "pics/17.jpg";
imgArray[17] = "pics/18.jpg";
imgArray[18] = "pics/19.jpg";
imgArray[19] = "pics/20.jpg";




function slideshow(slide_num) {
document.getElementById('mypic').src=imgArray[slide_num];
  
  
}

function slideshowUp() {
  num++;
  num = num % imgArray.length;
  slideshow(num);
}

function slideshowBack() {
  num--;
  if (num < 0) {num=imgArray.length-1;}
  num = num % imgArray.length;
  slideshow(num);
}