var image_dir = "images/";
var ImageNum = 0;
var TotalNum = 0;

imageArray = new Array();
imageArray[ImageNum++] = image_dir + "galbum97_1.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_2.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_3.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_4.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_5.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_6.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_7.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_8.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_9.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_10.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_11.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_12.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_13.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_14.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_15.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_16.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_17.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_18.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_19.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_20.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_21.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_22.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_23.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_24.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_25.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_26.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_27.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_28.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_29.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_30.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_31.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_32.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_33.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_34.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_35.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_36.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_37.jpg";
imageArray[ImageNum++] = image_dir + "galbum97_38.jpg";

TotalNum = ImageNum;
ImageNum = -1;

function AvanzaImage()
{
   ImageNum++;
   if (ImageNum == TotalNum)
     ImageNum=0;
   document.mainimage.src = imageArray[ImageNum];
}

function RetrocedeImage()
{
   ImageNum--;
   if (ImageNum == -1)
     ImageNum= TotalNum - 1;
   document.mainimage.src = imageArray[ImageNum];
}