Каптча (by Fuelen)

                        
<?php  



session_start();  



$alp='QWERTYUIOPASDFGHJKLZXCVBNM123446789';  



$len=strlen($alp);  



$code=NULL;  



$image = imagecreatetruecolor(72, 30);  



$x = NULL;  



$chars = mt_rand(4, 6);  



for($i=0; $i<$chars; $i++)  



{  



$x+=rand(7, 11);  



$code .= $symb = $alp{mt_rand(0,$len-1)};  



imagechar($image, 5, $x, mt_rand(2, 14),$symb, 0x00FFFF);  



}  







$_SESSION['code'] = $code;  



imagefilter($image, IMG_FILTER_EMBOSS);  



header('Content-Type: image/png');  







Imagepng($image);  



ImageDestroy($image);  







?>