var num4=0;

imgArray4 = [
  ['http://movermoms.org/programs/bookclub/previous/book4/photo_01.jpg','photo 1 mouseover text'],
  ['http://movermoms.org/programs/bookclub/previous/book4/photo_02.jpg','photo 2 mouseover text'],
  ['http://movermoms.org/programs/bookclub/previous/book4/photo_03.jpg','photo 3 mouseover text'],
  ['http://movermoms.org/programs/bookclub/previous/book4/photo_04.jpg','photo 4 mouseover text',]
  ]

function slideshow4(slide_num) {
  document.getElementById('mypic4').src=imgArray4[slide_num][0];
  document.getElementById('mypic4').alt=imgArray4[slide_num][1];
}

function slideshow4Up() {
  num4++;
  num4 = num4 % imgArray4.length;
  slideshow4(num4);
}

function slideshow4Back() {
  num4--;
  if (num4 < 0) {num3=imgArray4.length-1;}
  num4 = num4 % imgArray4.length;
  slideshow4(num4);
}