public function resimOlustur() 

{ 

    $md5_hash = md5(rand(0,999)); 

    $security_code = substr($md5_hash, 15, 5); 

    $_SESSION["security_code"] = $security_code;

    $width = 100; 

    $height = 20;  

    $image = ImageCreate($width, $height);  

    $white = ImageColorAllocate($image, 255, 255, 255); 

    $black = ImageColorAllocate($image, 0, 0, 0); 

    $grey = ImageColorAllocate($image, 204, 204, 204); 

    ImageFill($image, 0, 0, $black); 

    ImageString($image, 3, 30, 3, $security_code, $white); 

    ImageRectangle($image,0,0,$width-1,$height-1,$grey); 

    imageline($image, 0, $height/5, $width, $height/5, $grey); 

    imageline($image, $width/5, 0, $width/5, $height, $grey); 

    header("Content-Type: image/jpeg"); 

    ImageJpeg($image); 

    ImageDestroy($image);