/system/application/helpers/captcha_helper.php

<?php

if ( ! function_exists('load_captcha')) {

	function load_captcha(& $title, & $output, $lang, $captcha_images_number = 4, $enclosure = "&nbsp;") {

	    $images = array("basket", "corn", "gourd", "plant", "shovel", "sun", "sunflower", "tomato", "watercan", "wheat");

	    $images_name = array($lang['basket'], $lang['corn'], $lang['gourd'], $lang['plant'], $lang['shovel'], $lang['sun'], $lang['sunflower'], $lang['tomato'], $lang['watercan'], $lang['wheat']);

	    $chosen_nums = array(); //Chosen numbers

	    $chosen_images = array(); //Chosen images

	    

	    $cnt = count($images);

	    

	    if($captcha_images_number >= $cnt) {

	        return FALSE;

	    }

		for($i = 0; $i < $captcha_images_number; $i++) {

		    $rnd = mt_rand(0, $cnt - 1);

		    if(array_search($rnd, $chosen_nums) === FALSE) {

		    	$chosen_nums[] = $rnd;

		    	$chosen_images[] = $images[$rnd];

		    	$output .= "<img class='captcha_img' title='" . $i . "' src='" . css_url() . "system/application/assets/images/registration/captcha/" . $images[$rnd] . ".png' />" . $enclosure;

		    }

		    else {

		        $i--;

		    }

		}

		$rnd = mt_rand(0, $captcha_images_number - 1);

		$title = "<span class=\"captchaText\"><B>" . $images_name[$chosen_nums[$rnd]] . "</B>" .  $lang['captcha_choose']."</span>";

		

		$_SESSION['captcha'] = $rnd;

		

	    return $rnd;

	}

}