Измените

 

Warning: imagepng(/var/www/mojaopstina.rs/www-root/public/images/captcha/8d5f8983df8f8a83b577167b23b5a70c.png): failed to open stream: Permission denied in /var/www/mojaopstina.rs/www-root/library/Zend/Captcha/Image.php on line 563