var imgMax = 6;
var imgRandom = Math.floor(Math.random() * imgMax);
if(imgRandom == 0) document.write("<img src='index_imgs/image.jpg' width='180' height='300' />");
else if(imgRandom == 1) document.write("<img src='index_imgs/image2.jpg' width='180' height='300' />");
else if(imgRandom == 2) document.write("<img src='index_imgs/image3.jpg' width='180' height='300' />");
else if(imgRandom == 3) document.write("<img src='index_imgs/image4.jpg' width='180' height='300' />");
else if(imgRandom == 4) document.write("<img src='index_imgs/image5.jpg' width='180' height='300' />");
else if(imgRandom == 5) document.write("<img src='index_imgs/image6.jpg' width='180' height='300' />");