var num=0;

imgArray = [
  ['images/Investigations/Invest20091003_01.JPG','Multiple Light Anomalies','1/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_02.JPG','Light Anomaly','2/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_03.JPG','Light Anomaly','3/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_04.JPG','Light Anomaly','4/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_05.JPG','Light Anomaly','5/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_06.JPG','Multiple Light Anomalies','6/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_07.JPG','Multiple Light Anomalies','7/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_08.JPG','Light Anomaly','8/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_09.JPG','Light Anomaly','9/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_10.JPG','Light Anomaly','10/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_11.JPG','Multiple Light Anomalies','11/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_12.JPG','Multiple Light Anomalies','12/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_13.JPG','Light Anomaly','13/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_14.JPG','Multiple Light Anomalies','14/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_15.JPG','Multiple Light Anomalies','15/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_16.JPG','Light Anomaly','16/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_17.JPG','Multiple Light Anomalies','17/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_18.JPG','Light Anomaly','18/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_19.JPG','Light Anomaly','19/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_20.JPG','Light Anomaly','20/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_21.JPG','Multiple Light Anomalies','21/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_22.JPG','Light Anomaly','22/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_23.JPG','Multiple Light Anomalies','23/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_24.JPG','Light Anomaly','24/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_25.JPG','Light Anomaly','25/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_26.JPG','Multiple Light Anomalies','26/28 - Multiple Light Anomalies'],
  ['images/Investigations/Invest20091003_27.JPG','Light Anomaly','27/28 - Light Anomaly'],
  ['images/Investigations/Invest20091003_28.JPG','Light Anomaly','28/28 - Light Anomaly']
]

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);
}