How to get unique random image and not the same shape??

hi,

I am trying to get 3 random images out of a pool of 15 images(let say shapes square, circle and
, but the images must be
- unique so no repeat
- some shapes just once
- some images more "random", so a higher change to appear

for the non repeat i use

	function non_repeat($min, $max, $count, $sort = false)
	{
		/**
		*	method outputs an unique array within a range 
		*	
		*	$min	begin range
		*	$max 	end range
		*	$count	 output
		**/
		if ($max - $min < $count) {
			return false;
		}
		$arr = range($min, $max);
		$arr_rnd = array_rand($arr, $count);
		foreach ($arr_rnd as $each) {
			$nonrepeatarray[] = $arr[$each];
		}
		if (!$sort) {    
			shuffle($nonrepeatarray);
		}
		return $nonrepeatarray;
	}

Code (markup):

What should i do next??

 

hi..
try to registering your image to the session, so it will no repeat