var num=0;

imgArray = [
  ['photo-01.jpg','photo 1 mouseover text','Photo 1'],
  ['photo-02.jpg','photo 2 mouseover text','Photo 2'],
  ['photo-03.jpg','photo 3 mouseover text','Photo 3'],
  ['photo-04.jpg','photo 4 mouseover text','Photo 4'],
  ['photo-05.jpg','photo 5 mouseover text','Photo 5'],
  ['photo-06.jpg','photo 6 mouseover text','Photo 6'],
  ['photo-07.jpg','photo 7 mouseover text','Photo 7'],
  ['photo-08.jpg','photo 8 mouseover text','Photo 8'],
  ['photo-09.jpg','photo 9 mouseover text','Photo 9']
  ]

function slideshow(slide_num) {
  document.getElementById('mypic').src=imgArray[slide_num][0];
  document.getElementById('mypic').alt=imgArray[slide_num][1];
  document.getElementById('burns').innerHTML=imgArray[slide_num][2];
}

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);
}