GD image imagecreatetruecolor() error.

Changed my php.ini file ;extension=gd to extension=gd

Load a view on 'test' url file code was

<?php
phpinfo();
?>

and found the gd was there in the information and authors are Rasmus Lerdorf, Stig Bakken, Jim Winstead, Jouni Ahto, Ilia Alshanetsky, Pierre-Alain Joye, Marcus Boerger, Mark Randall

While visiting to the /login/admin url getting this error

Call to undefined function Gregwar\Captcha\imagecreatetruecolor()