images = [
     '<img src="images/thumbs/hat1.jpg" alt="shower hat"/>',
     '<img src="images/thumbs/hat2.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat3.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat4.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat5.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat6.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat7.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat8.jpg" alt="shower hat"/>',
     '<img src="images/thumbs/hat9.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat10.jpg" alt="shower hat" />',
     '<img src="images/thumbs/hat11.jpg" alt="shower hat"/>',
     '<img src="images/thumbs/hat12.jpg" alt="shower hat" />'
     ]

var num_display = 4;

function random_image() {

	for(i=0;i<num_display;i++){

		var ran = Math.floor(Math.random() * images.length)
		document.write(images[ran]);
		images.splice(ran,1)
	}

}